diff --git a/takway/clients/web_socket_client_utils.py b/takway/clients/web_socket_client_utils.py
index 50601c9..114b56d 100644
--- a/takway/clients/web_socket_client_utils.py
+++ b/takway/clients/web_socket_client_utils.py
@@ -318,6 +318,7 @@ class WebSocketClinet:
             if is_end:
                 # print("put None to client queue.")
                 self.client_queue.put(None)
+                print(f"{datetime.now()}: conversation is end.")
             return True
         else:
             return False