英语中动词不能做主语,那祈使句怎么回事,谁能帮我解释一下啊

动词不能直接做主,需用动名词(短语)和不定式(短语).eg seeing is believing.
doing nothing means death . it's not that hard to get your weight under contral.
祈使句由于说话者和听话者已明确主语故省略. (you) shut up !( everyone ) be quite.
希望我的回答能让你满意