当我们在网上下载好tensorflow 2.x的安装包后，可方便离线安装，pip安装方法：
pip install --no-index --find-link="." tensorflow-gpu==2.5.0
过程中报警Cannot uninstall ‘wrapt’. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
将离线安装包中的wrapt-1.12.1.tar.gz解压，然后打开wrapt-1.12.1文件夹，在该文件夹下运行 python setup.py install
安装好wrapt-1.12.1后，再重新安装tensorflow
pip install --no-index --find-link="." tensorflow-gpu==2.5.0
即可成功安装！
