No module named 'tkinter'_debian no module named tkinter

mrc@mrc-Inspiron-7472:/$ workon env3
(env3) mrc@mrc-Inspiron-7472:/$ pip install --upgrade pip -i https://pypi.tuna.tsinghua.edu.cn/simple
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Collecting pip
  Using cached https://pypi.tuna.tsinghua.edu.cn/packages/f9/fb/863012b13912709c13cf5cfdbfb304fa6c727659d6290438e1a88df9d848/pip-19.1-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 19.0.3
    Uninstalling pip-19.0.3:
      Successfully uninstalled pip-19.0.3
Successfully installed pip-19.1
(env3) mrc@mrc-Inspiron-7472:/$ pip install tkinter -i https://pypi.tuna.tsinghua.edu.cn/simple
Looking in indexes: https://pypi.tuna.tsinghua.edu.cn/simple
Collecting tkinter
  ERROR: Could not find a version that satisfies the requirement tkinter (from versions: none)
ERROR: No matching distribution found for tkinter
(env3) mrc@mrc-Inspiron-7472:/$ pip install tkinter -i http://pypi.douban.com/simple/
Looking in indexes: http://pypi.douban.com/simple/
Collecting tkinter
  WARNING: The repository located at pypi.douban.com is not a trusted or secure host and is being ignored. If this repository is available via HTTPS we recommend you use HTTPS instead, otherwise you may silence this warning and allow it anyway with '--trusted-host pypi.douban.com'.
  ERROR: Could not find a version that satisfies the requirement tkinter (from versions: none)
ERROR: No matching distribution found for tkinter
(env3) mrc@mrc-Inspiron-7472:/$ pip install tkinter -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com
Looking in indexes: http://pypi.douban.com/simple/
Collecting tkinter
  ERROR: Could not find a version that satisfies the requirement tkinter (from versions: none)
ERROR: No matching distribution found for tkinter
 
 
 
发现并不是清华源不好，
 
 
 
(env3) mrc@mrc-Inspiron-7472:/$ sudo apt-get install python3-tk
[sudo] mrc 的密码：
正在读取软件包列表... 完成
正在分析软件包的依赖关系树       
正在读取状态信息... 完成       
将会同时安装下列软件：
  blt libtcl8.6 libtk8.6 tk8.6-blt2.5
建议安装：
  blt-demo tcl8.6 tk8.6 tix python3-tk-dbg
下列【新】软件包将被安装：
  blt libtcl8.6 libtk8.6 python3-tk tk8.6-blt2.5
升级了 0 个软件包，新安装了 5 个软件包，要卸载 0 个软件包，有 30 个软件包未被升级。
需要下载 2,252 kB 的归档。
解压缩后会消耗 9,231 kB 的额外空间。
您希望继续执行吗？ [Y/n] y
获取:1 http://cn.archive.ubuntu.com/ubuntu bionic/main amd64 libtcl8.6 amd64 8.6.8+dfsg-3 [881 kB]
获取:2 http://cn.archive.ubuntu.com/ubuntu bionic/main amd64 libtk8.6 amd64 8.6.8-4 [693 kB]
获取:3 http://cn.archive.ubuntu.com/ubuntu bionic/main amd64 tk8.6-blt2.5 amd64 2.5.3+dfsg-4 [572 kB]
获取:4 http://cn.archive.ubuntu.com/ubuntu bionic/main amd64 blt amd64 2.5.3+dfsg-4 [4,944 B]
获取:5 http://cn.archive.ubuntu.com/ubuntu bionic/main amd64 python3-tk amd64 3.6.5-3 [100 kB]
已下载 2,252 kB，耗时 16秒 (137 kB/s)                                          
正在选中未选择的软件包 libtcl8.6:amd64。
(正在读取数据库 ... 系统当前共安装有 173917 个文件和目录。)
正准备解包 .../libtcl8.6_8.6.8+dfsg-3_amd64.deb  ...
正在解包 libtcl8.6:amd64 (8.6.8+dfsg-3) ...
正在选中未选择的软件包 libtk8.6:amd64。
正准备解包 .../libtk8.6_8.6.8-4_amd64.deb  ...
正在解包 libtk8.6:amd64 (8.6.8-4) ...
 
 
OK