在Ubuntu16.04中将python3设置为默认环境后，打开终端出现了如下错误：
/usr/bin/python: Error while finding spec for 'virtualenvwrapper.hook_loader' (<class 'ImportError'>: No module named 'virtualenvwrapper')
virtualenvwrapper.sh: There was a problem running the initialization hooks.
If Python could not import the module virtualenvwrapper.hook_loader,
check that virtualenvwrapper has been installed for
VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
set properly.依次执行以下命令：
sudo apt-get install python3-pipsudo pip3 install virtualenv virtualenvwrappersource .bashrc 即可解决。