diff --git a/docs/user_manual/Small_Materialized_Aggrates.md b/docs/user_manual/Small_Materialized_Aggrates.md
index dc2d9e41ed3e7c52d050f239f6a5bf413b7db2b8..e13a623afb144a3f785fdfc59f3e7e880667463c 100644
--- a/docs/user_manual/Small_Materialized_Aggrates.md
+++ b/docs/user_manual/Small_Materialized_Aggrates.md
@@ -39,4 +39,4 @@ Users can also drop a time-range-wise SMA like below:
 # drop the sma index
 drop sma_index sma_5min on st;
 ```
-**NOTE: Creating a SMA index is a heavy operation which may take a long time and block the write operation. So create the time-range-wise SMA when creating the table or when there are not too much data.**
\ No newline at end of file
+**NOTE: Creating an SMA index is a heavy operation which may take a long time and block the write operation. So create the time-range-wise SMA when creating the table or when there are not too much data.**
\ No newline at end of file