Question

非谓语动词可以做主语吗

Answer 1

可以，doing/to do做主语，但过去分分词不可以，例：
Learning different things is a important way to expand one's horizon.
学习不同的东西是拓宽视野的重要途径。
To establish a supply bases is very crucial for the underground exploration.
建立供应基地是地下勘探的关键。

Answer 2

Eating more vegetables is good for our health. 动名词做主语。
To be a good teacher is my dream. 动词不定式做主语。