diff --git a/convert.py b/convert.py
index 4184160..75ad9d2 100644
--- a/convert.py
+++ b/convert.py
@@ -1,9 +1,5 @@
-import argparse
 import zipfile
 import opencc
-import glob
-import time
-from io import BytesIO
 from pathlib import Path
 
 # only initailize OpenCC once, or it would be very slow
@@ -45,6 +41,11 @@ def s2t(text):
     return converter.convert(text)
 
 if __name__ == "__main__":
+    import argparse
+    import glob
+    import time
+    from io import BytesIO
+
     parser = argparse.ArgumentParser(description="Convert simplified chinese to traditional chinese in epub.")
     parser.add_argument('file', nargs='+', help="epub files")
     args = parser.parse_args()
@@ -66,4 +67,4 @@ if __name__ == "__main__":
             output = convert_epub(fn, buffer)
             with open(s2t(fn), "wb") as f:
                 f.write(buffer.getvalue())
-            print(f"File {fn} is successfully converted. Time elapsed: {round(time.time() - t, 2)}s")
\ No newline at end of file
+            print(f"File {fn} is successfully converted. Time elapsed: {round(time.time() - t, 2)}s")