diff --git a/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md b/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
index c7fe3ae27f..30df526a8b 100644
--- a/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
+++ b/docs/design_docs/datanode_flowgraph_recovery_design_0604_2021.md
@@ -10,7 +10,7 @@ B. Only when datanode flushes, datanode will update every segment's position.
 An optimization: update position of
 
 - a. Current flushing segment
-- b. StartPosition of segments never been flushed.
+- b. StartPosition of segments has never been flushed.
   C. DataNode auto-flush is a valid flush.
   D. DDL messages are now in DML Vchannels.