diff --git a/src/archive/zip/writer.go b/src/archive/zip/writer.go
index 5ce66e6be5e..3a9292e3807 100644
--- a/src/archive/zip/writer.go
+++ b/src/archive/zip/writer.go
@@ -52,7 +52,7 @@ func (w *Writer) Flush() error {
 }
 
 // Close finishes writing the zip file by writing the central directory.
-// It does not (and can not) close the underlying writer.
+// It does not (and cannot) close the underlying writer.
 func (w *Writer) Close() error {
 	if w.last != nil && !w.last.closed {
 		if err := w.last.close(); err != nil {
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go
index 8b4e2bfd58e..90c2584c7fb 100644
--- a/src/cmd/cgo/doc.go
+++ b/src/cmd/cgo/doc.go
@@ -133,7 +133,7 @@ C's union types are represented as a Go byte array with the same length.
 
 Go structs cannot embed fields with C types.
 
-Go code can not refer to zero-sized fields that occur at the end of
+Go code cannot refer to zero-sized fields that occur at the end of
 non-empty C structs.  To get the address of such a field (which is the
 only operation you can do with a zero-sized field) you must take the
 address of the struct and add the size of the struct.
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index fb5049c1a1d..5bfdef785c1 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -432,7 +432,7 @@ func (p *Package) loadDWARF(f *File, names []*Name) {
 			fmt.Fprintf(&b, "\t0,\n")
 		}
 	}
-	// for the last entry, we can not use 0, otherwise
+	// for the last entry, we cannot use 0, otherwise
 	// in case all __cgodebug_data is zero initialized,
 	// LLVM-based gcc will place the it in the __DATA.__common
 	// zero-filled section (our debug/macho doesn't support
@@ -2025,7 +2025,7 @@ func (c *typeConv) Struct(dt *dwarf.StructType, pos token.Pos) (expr *ast.Struct
 	// We can't permit that, because then the size of the Go
 	// struct will not be the same as the size of the C struct.
 	// Our only option in such a case is to remove the field,
-	// which means that it can not be referenced from Go.
+	// which means that it cannot be referenced from Go.
 	for off > 0 && sizes[len(sizes)-1] == 0 {
 		n := len(sizes)
 		fld = fld[0 : n-1]
diff --git a/src/cmd/compile/internal/gc/lex.go b/src/cmd/compile/internal/gc/lex.go
index 54c69c54491..0f8b20cea03 100644
--- a/src/cmd/compile/internal/gc/lex.go
+++ b/src/cmd/compile/internal/gc/lex.go
@@ -255,7 +255,7 @@ func Main() {
 		msanpkg.Name = "msan"
 	}
 	if flag_race != 0 && flag_msan != 0 {
-		log.Fatal("can not use both -race and -msan")
+		log.Fatal("cannot use both -race and -msan")
 	} else if flag_race != 0 || flag_msan != 0 {
 		instrumenting = true
 	}
diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index ae426088ea1..51931769d5a 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -2337,7 +2337,7 @@ func TestGoGetHTTPS404(t *testing.T) {
 	tg.run("get", "bazil.org/fuse/fs/fstestutil")
 }
 
-// Test that you can not import a main package.
+// Test that you cannot import a main package.
 func TestIssue4210(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index d8e7cb77af3..28c36160b52 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -199,7 +199,7 @@ type Scanner interface {
 	//    time.Time
 	//    nil - for NULL values
 	//
-	// An error should be returned if the value can not be stored
+	// An error should be returned if the value cannot be stored
 	// without loss of information.
 	Scan(src interface{}) error
 }
diff --git a/src/log/syslog/syslog.go b/src/log/syslog/syslog.go
index 4bf447626f2..0e342242ecc 100644
--- a/src/log/syslog/syslog.go
+++ b/src/log/syslog/syslog.go
@@ -85,7 +85,7 @@ type Writer struct {
 }
 
 // This interface and the separate syslog_unix.go file exist for
-// Solaris support as implemented by gccgo.  On Solaris you can not
+// Solaris support as implemented by gccgo.  On Solaris you cannot
 // simply open a TCP connection to the syslog daemon.  The gccgo
 // sources have a syslog_solaris.go file that implements unixSyslog to
 // return a type that satisfies this interface and simply calls the C
diff --git a/src/net/http/server.go b/src/net/http/server.go
index 5e3b6084ae3..1b5cda3159a 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -2032,7 +2032,7 @@ const (
 	// For HTTP/2, StateActive fires on the transition from zero
 	// to one active request, and only transitions away once all
 	// active requests are complete. That means that ConnState
-	// can not be used to do per-request work; ConnState only notes
+	// cannot be used to do per-request work; ConnState only notes
 	// the overall state of the connection.
 	StateActive
 
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index 1e3ea11d9c5..feedb3420d8 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -418,7 +418,7 @@ func (t *Transport) CloseIdleConnections() {
 // CancelRequest cancels an in-flight request by closing its connection.
 // CancelRequest should only be called after RoundTrip has returned.
 //
-// Deprecated: Use Request.Cancel instead. CancelRequest can not cancel
+// Deprecated: Use Request.Cancel instead. CancelRequest cannot cancel
 // HTTP/2 requests.
 func (t *Transport) CancelRequest(req *Request) {
 	t.reqMu.Lock()
diff --git a/src/os/signal/doc.go b/src/os/signal/doc.go
index 80e66cffe53..9ee547b15db 100644
--- a/src/os/signal/doc.go
+++ b/src/os/signal/doc.go
@@ -11,7 +11,7 @@ package on Windows and Plan 9, see below.
 Types of signals
 
 The signals SIGKILL and SIGSTOP may not be caught by a program, and
-therefore can not be affected by this package.
+therefore cannot be affected by this package.
 
 Synchronous signals are signals triggered by errors in program
 execution: SIGBUS, SIGFPE, and SIGSEGV. These are only considered
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index fef8add46fe..f632f7ab5af 100644
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -340,7 +340,7 @@ var racecgosync uint64 // represents possible synchronization in C code
 // When and if we implement a moving garbage collector,
 // cgoCheckPointer will pin the pointer for the duration of the cgo
 // call.  (This is necessary but not sufficient; the cgo program will
-// also have to change to pin Go pointers that can not point to Go
+// also have to change to pin Go pointers that cannot point to Go
 // pointers.)
 
 // cgoCheckPointer checks if the argument contains a Go pointer that
diff --git a/src/runtime/mbarrier.go b/src/runtime/mbarrier.go
index 45086c43cdd..1204e8143ef 100644
--- a/src/runtime/mbarrier.go
+++ b/src/runtime/mbarrier.go
@@ -100,7 +100,7 @@ func gcmarkwb_m(slot *uintptr, ptr uintptr) {
 // related operations. In particular there are times when the GC assumes
 // that the world is stopped but scheduler related code is still being
 // executed, dealing with syscalls, dealing with putting gs on runnable
-// queues and so forth. This code can not execute write barriers because
+// queues and so forth. This code cannot execute write barriers because
 // the GC might drop them on the floor. Stopping the world involves removing
 // the p associated with an m. We use the fact that m.p == nil to indicate
 // that we are in one these critical section and throw if the write is of
diff --git a/src/runtime/mfixalloc.go b/src/runtime/mfixalloc.go
index 8653a6a99fc..569a304cf45 100644
--- a/src/runtime/mfixalloc.go
+++ b/src/runtime/mfixalloc.go
@@ -30,8 +30,8 @@ type fixalloc struct {
 }
 
 // A generic linked list of blocks.  (Typically the block is bigger than sizeof(MLink).)
-// Since assignments to mlink.next will result in a write barrier being preformed
-// this can not be used by some of the internal GC structures. For example when
+// Since assignments to mlink.next will result in a write barrier being performed
+// this cannot be used by some of the internal GC structures. For example when
 // the sweeper is placing an unmarked object on the free list it does not want the
 // write barrier to be called since that could result in the object being reachable.
 type mlink struct {
diff --git a/src/runtime/mstats.go b/src/runtime/mstats.go
index 368687d0064..8ae636077b9 100644
--- a/src/runtime/mstats.go
+++ b/src/runtime/mstats.go
@@ -165,7 +165,7 @@ type MemStats struct {
 
 // Size of the trailing by_size array differs between Go and C,
 // and all data after by_size is local to runtime, not exported.
-// NumSizeClasses was changed, but we can not change Go struct because of backward compatibility.
+// NumSizeClasses was changed, but we cannot change Go struct because of backward compatibility.
 // sizeof_C_MStats is what C thinks about size of Go struct.
 var sizeof_C_MStats = unsafe.Offsetof(memstats.by_size) + 61*unsafe.Sizeof(memstats.by_size[0])
 
@@ -192,7 +192,7 @@ func readmemstats_m(stats *MemStats) {
 	updatememstats(nil)
 
 	// Size of the trailing by_size array differs between Go and C,
-	// NumSizeClasses was changed, but we can not change Go struct because of backward compatibility.
+	// NumSizeClasses was changed, but we cannot change Go struct because of backward compatibility.
 	memmove(unsafe.Pointer(stats), unsafe.Pointer(&memstats), sizeof_C_MStats)
 
 	// Stack numbers are part of the heap numbers, separate those out for user consumption
diff --git a/src/runtime/norace_linux_test.go b/src/runtime/norace_linux_test.go
index bbf9d0b4139..049801d3fc5 100644
--- a/src/runtime/norace_linux_test.go
+++ b/src/runtime/norace_linux_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// The file contains tests that can not run under race detector for some reason.
+// The file contains tests that cannot run under race detector for some reason.
 // +build !race
 
 package runtime_test
diff --git a/src/runtime/norace_test.go b/src/runtime/norace_test.go
index 3681bf190d2..e9b39b2f455 100644
--- a/src/runtime/norace_test.go
+++ b/src/runtime/norace_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// The file contains tests that can not run under race detector for some reason.
+// The file contains tests that cannot run under race detector for some reason.
 // +build !race
 
 package runtime_test
diff --git a/src/runtime/os1_darwin.go b/src/runtime/os1_darwin.go
index 5c00407b2fc..19bb0f16e07 100644
--- a/src/runtime/os1_darwin.go
+++ b/src/runtime/os1_darwin.go
@@ -157,7 +157,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	// Initialize signal handling.
 	_g_ := getg()
diff --git a/src/runtime/os1_dragonfly.go b/src/runtime/os1_dragonfly.go
index bf3e1ccb839..7e4f84e6a3c 100644
--- a/src/runtime/os1_dragonfly.go
+++ b/src/runtime/os1_dragonfly.go
@@ -133,7 +133,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	_g_ := getg()
 
diff --git a/src/runtime/os1_freebsd.go b/src/runtime/os1_freebsd.go
index 79d995476e8..f00fdf4389a 100644
--- a/src/runtime/os1_freebsd.go
+++ b/src/runtime/os1_freebsd.go
@@ -136,7 +136,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	_g_ := getg()
 
diff --git a/src/runtime/os1_linux.go b/src/runtime/os1_linux.go
index b38cfc14f91..2d53b934f56 100644
--- a/src/runtime/os1_linux.go
+++ b/src/runtime/os1_linux.go
@@ -225,7 +225,7 @@ func sigblock() {
 func gettid() uint32
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	// Initialize signal handling.
 	_g_ := getg()
diff --git a/src/runtime/os1_nacl.go b/src/runtime/os1_nacl.go
index dab205de6a3..5526d906d81 100644
--- a/src/runtime/os1_nacl.go
+++ b/src/runtime/os1_nacl.go
@@ -30,7 +30,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	_g_ := getg()
 
diff --git a/src/runtime/os1_netbsd.go b/src/runtime/os1_netbsd.go
index eab8eb87024..e32df9585c6 100644
--- a/src/runtime/os1_netbsd.go
+++ b/src/runtime/os1_netbsd.go
@@ -167,7 +167,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	_g_ := getg()
 	_g_.m.procid = uint64(lwp_self())
diff --git a/src/runtime/os1_plan9.go b/src/runtime/os1_plan9.go
index 7506d591df4..99110779110 100644
--- a/src/runtime/os1_plan9.go
+++ b/src/runtime/os1_plan9.go
@@ -33,7 +33,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	// Mask all SSE floating-point exceptions
 	// when running on the 64-bit kernel.
diff --git a/src/runtime/os1_windows.go b/src/runtime/os1_windows.go
index a28e11e088d..8d46bca36d5 100644
--- a/src/runtime/os1_windows.go
+++ b/src/runtime/os1_windows.go
@@ -399,7 +399,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	var thandle uintptr
 	stdcall7(_DuplicateHandle, currentProcess, currentThread, currentProcess, uintptr(unsafe.Pointer(&thandle)), 0, 0, _DUPLICATE_SAME_ACCESS)
diff --git a/src/runtime/os3_solaris.go b/src/runtime/os3_solaris.go
index 7ebb35c8e9c..fdc817d3f79 100644
--- a/src/runtime/os3_solaris.go
+++ b/src/runtime/os3_solaris.go
@@ -208,7 +208,7 @@ func sigblock() {
 }
 
 // Called to initialize a new m (including the bootstrap m).
-// Called on the new thread, can not allocate memory.
+// Called on the new thread, cannot allocate memory.
 func minit() {
 	_g_ := getg()
 	asmcgocall(unsafe.Pointer(funcPC(miniterrno)), unsafe.Pointer(&libc____errno))
diff --git a/src/runtime/sys_darwin_arm.s b/src/runtime/sys_darwin_arm.s
index 82a8db99141..6b6437dddd1 100644
--- a/src/runtime/sys_darwin_arm.s
+++ b/src/runtime/sys_darwin_arm.s
@@ -261,7 +261,7 @@ cont:
 	MOVW    R1, 24(R6)
 
 	// switch stack and g
-	MOVW	R6, R13 // sigtramp can not re-entrant, so no need to back up R13.
+	MOVW	R6, R13 // sigtramp is not re-entrant, so no need to back up R13.
 	MOVW	R5, g
 
 	BL	(R0)
diff --git a/src/runtime/sys_darwin_arm64.s b/src/runtime/sys_darwin_arm64.s
index d0034d5a33f..a3b851d2fc8 100644
--- a/src/runtime/sys_darwin_arm64.s
+++ b/src/runtime/sys_darwin_arm64.s
@@ -245,7 +245,7 @@ cont:
 	MOVD	R1, 48(R6)
 
 	// switch stack and g
-	MOVD	R6, RSP	// sigtramp can not re-entrant, so no need to back up RSP.
+	MOVD	R6, RSP	// sigtramp is not re-entrant, so no need to back up RSP.
 	MOVD	R5, g
 
 	BL	(R0)
diff --git a/src/runtime/vdso_linux_amd64.go b/src/runtime/vdso_linux_amd64.go
index 38914bb2b9f..42571e063cd 100644
--- a/src/runtime/vdso_linux_amd64.go
+++ b/src/runtime/vdso_linux_amd64.go
@@ -263,7 +263,7 @@ func vdso_find_version(info *vdso_info, ver *version_key) int32 {
 		def = (*elf64Verdef)(add(unsafe.Pointer(def), uintptr(def.vd_next)))
 	}
 
-	return -1 // can not match any version
+	return -1 // cannot match any version
 }
 
 func vdso_parse_symbols(info *vdso_info, version int32) {
diff --git a/src/sync/pool.go b/src/sync/pool.go
index 381af0bead5..4fb1a1af9d9 100644
--- a/src/sync/pool.go
+++ b/src/sync/pool.go
@@ -149,7 +149,7 @@ func (p *Pool) getSlow() (x interface{}) {
 func (p *Pool) pin() *poolLocal {
 	pid := runtime_procPin()
 	// In pinSlow we store to localSize and then to local, here we load in opposite order.
-	// Since we've disabled preemption, GC can not happen in between.
+	// Since we've disabled preemption, GC cannot happen in between.
 	// Thus here we must observe local at least as large localSize.
 	// We can observe a newer/larger local, it is fine (we must observe its zero-initialized-ness).
 	s := atomic.LoadUintptr(&p.localSize) // load-acquire