can do nothing but do have no choice/alternative but to do
might as wellwould rather
难点解析
1.接不定式或动名词在意思上有区别的动词：
fmean to do想要(做某事)propose to do打算(做某事)
mean doing意味(做某事)propose doing建议(做某事)
fforget to do忘记(要做的事)remember to do记得(要做某事)
forget doing忘记(已做的事)remember doing记得(已做过的事)
regret to do(对将要做的事)遗憾go on to do继而(做另一件事)
regret doing(对已做过的事)后悔go on doing继续(做原来的事)
fstop to do停下来去做另一件事
stop doing停止正在做的事
2.下列动词短语中的to是介词，后面应接动名词或名词：
object to，resort to，react to，contribute to，look forward to，be accustomed to，be committed to.be ex.
posed to，be subjected to，be devoted to，be dedicated to，be opposed to，be reconciled to.be contrary to