diff --git a/q4/.gitkeep b/q4/.gitkeep
new file mode 100644
index 0000000..b22e7b9
--- /dev/null
+++ b/q4/.gitkeep
@@ -0,0 +1 @@
+# 此目录用于存放学生提交的文件，请勿删除
\ No newline at end of file