无法在python 3中导入urllib.request模块

Question

我正在使用 Python 3 中的 Think Python 一书执行代码。代码如下。

#!/usr/bin/env python3
# -*- encoding: utf-8 -*-

import urllib.request

conn = urllib.request.urlopen('http://thinkpython.com/secret.html')
for line in conn:
    print(line.strip())

当我在机器的终端中执行此代码时，得到以下输出。

Traceback (most recent call last):
  File "secret.py", line 4, in <module>
    import urllib.request
  File "/usr/lib/python3.6/urllib/request.py", line 84, in <module>
    import base64
  File "/usr/lib/python3.6/base64.py", line 10, in <module>
    import struct
  File "/usr/lib/python3.6/struct.py", line 13, in <module>
    from _struct import *
ModuleNotFoundError: No module named '_struct'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook
    from apport.fileutils import likely_packaged, get_recent_crashes
  File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>
    from apport.report import Report
  File "/usr/lib/python3/dist-packages/apport/report.py", line 12, in <module>
    import subprocess, tempfile, os.path, re, pwd, grp, os, time
  File "/usr/lib/python3.6/subprocess.py", line 136, in <module>
    import _posixsubprocess
ModuleNotFoundError: No module named '_posixsubprocess'

Original exception was:
Traceback (most recent call last):
  File "secret.py", line 4, in <module>
    import urllib.request
  File "/usr/lib/python3.6/urllib/request.py", line 84, in <module>
    import base64
  File "/usr/lib/python3.6/base64.py", line 10, in <module>
    import struct
  File "/usr/lib/python3.6/struct.py", line 13, in <module>
    from _struct import *
ModuleNotFoundError: No module named '_struct'

我在Anaconda中执行了相同的代码，并且得到了正确的输出。任何人都可以帮助我解决这个问题。