Couldn't find a tree builder with the features you requested: html.parser.下载lxml

Couldn’t find a tree builder with the features you requested: html.parser. Do you need to install a parser library?

可能1：解析器名写错了：html.parser
可能2：解析器不对：将解析器换为lxml

下载lxml：

如果是Pycharm，直接在File | Settings | Project: Python编译 | Project Interpreter”搜索添加lxml，install即可。
或者在cmd中：pip install lxml
(pip版本不够，根据提示upgrade）
前提是：pip要与你所用的python在同一个位置。