diff --git a/docs/design_docs/proxy.md b/docs/design_docs/proxy.md
index 91f6f3f6e8..9bff8c0556 100644
--- a/docs/design_docs/proxy.md
+++ b/docs/design_docs/proxy.md
@@ -90,7 +90,7 @@ the cache from Root Coordinator. At the same time, in order to keep the consiste
 of meta information in Root Coordinator, it will inform all Proxies to clear the related meta cache, and any newer
 requests will get the latest meta information.
 
-For inserts to a collection which is auto_id configured in the collection schema, Proxy assigns a primary key for
+For inserts to a collection that is auto_id configured in the collection schema, Proxy assigns a primary key for
 every row of insert request. For now the only supported data type of auto-generated primary field is `int64`. Proxy 
 applies for a batch of primary keys from Root Coordinator, and caches them for local assignments. When the primary keys in cache
 is not enough, Proxy will continue to apply for another batch of primary keys.