diff --git a/src/pkg/io/io.go b/src/pkg/io/io.go
index 629b9fb75f..54bf159eb4 100644
--- a/src/pkg/io/io.go
+++ b/src/pkg/io/io.go
@@ -179,7 +179,7 @@ type ReaderAt interface {
 // seek offset.
 //
 // Clients of WriteAt can execute parallel WriteAt calls on the same
-// destination if the ranges are not overlapping.
+// destination if the ranges do not overlap.
 type WriterAt interface {
 	WriteAt(p []byte, off int64) (n int, err error)
 }