Refine the sentence

Author: hezhizhen

content/en/docs/concepts/services-networking/service.md

@@ -74,7 +74,7 @@ a new instance.
 The name of a Service object must be a valid
 [DNS label name](/docs/concepts/overview/working-with-objects/names#dns-label-names).
 
-For example, suppose you have a set of Pods and each of them listens on TCP port 9376
+For example, suppose you have a set of Pods where each listens on TCP port 9376
 and contains a label `app=MyApp`:
 
 ```yaml