seem to be doing sth ,seem to do ,seem to have done sth

回答1：

seem to be doing sth表示不定式的动作和主句中seem是同一个时态，比如，He seems to be doing his homework. 他好像正在做作业；

seem to do 表示不定式的动作发生在主句动词seem之后，比如It seems to rain. 好像要下雨了。 rain的动作，是发生在seem之后的；

seem to have done sth表示不定式的动作发生在主句动词seem之前，比如 she seems to have finished her homework. 她好像做完了她的家庭作业。finish的动作发生在seem之前

回答2：

seem to be doing sth表示不定式的动作和主句中seem是同一个时态，比如，He seems to be doing his homework. 他好像正在做作业；

seem to do 表示不定式的动作发生在主句动词seem之后，比如It seems to rain. 好像要下雨了。 rain的动作，是发生在seem之后的；

seem to have done sth表示不定式的动作发生在主句动词seem之前，比如 she seems to have finished her homework. 她好像做完了她的家庭作业。finish的动作发生在seem之前

希望能对您有所帮助

回答3：

seem to be doing sth 似乎正在作某事
seem to have done sth 似乎已经做过某事
seem to do sth 似乎将要作某事

回答4：

seem to be doing sth 看上去（好像）正在做。。。
seem to do 看上去在做
seem to have done sth 看上去已经做了。。