diff --git a/src/crypto/x509/cert_pool.go b/src/crypto/x509/cert_pool.go
index 5381f0d659..86aba6710d 100644
--- a/src/crypto/x509/cert_pool.go
+++ b/src/crypto/x509/cert_pool.go
@@ -47,7 +47,7 @@ func (s *CertPool) copy() *CertPool {
 
 // SystemCertPool returns a copy of the system cert pool.
 //
-// Any mutations to a returned pool are not written to disk and do
+// Any mutations to the returned pool are not written to disk and do
 // not affect any other pool returned by SystemCertPool.
 //
 // New changes in the the system cert pool might not be reflected