已经在 cmd中下载了sklearn，无法在pycharm中下载sklearn。

问题遇到的现象和发生背景

错误提示：
ERROR: Failed building wheel for scikit-learn
ERROR: Could not build wheels for scikit-learn which use PEP 517 and cannot be installed directly

You are using pip version 21.1.2; however, version 21.3.1 is available.

让你更新下pip的版本。
python -m pip install --upgrade pip