diff --git a/index.js b/index.js
index 2d7e6834fb6366b3120c7a37cc5f637bc4a33928..5fd1d723c5e14f1d92963318bb8380f3b7d2b306 100644
--- a/index.js
+++ b/index.js
@@ -1 +1,7 @@
-console.log("欢迎来到 InsCode");
\ No newline at end of file
+function aa (str) {
+  const englishRegex = /^[a-zA-Z]+$/;
+  return englishRegex.test(str);
+}
+
+const a = aa('this is a good idea')
+console.log(a);
\ No newline at end of file