diff --git a/nemu/src/monitor/sdb/addrexp.y b/nemu/src/monitor/sdb/addrexp.y
index df4bc56..8e7df9a 100644
--- a/nemu/src/monitor/sdb/addrexp.y
+++ b/nemu/src/monitor/sdb/addrexp.y
@@ -11,7 +11,7 @@
     #include <stdio.h>
     #include <stdlib.h>
     void yyerror(word_t *result, const char *err) {
-      Error("Expression syntax error: %s", err);
+      Error("%s", err);
     }
 %}