what we should do is后面到底加ing还是to do?

what we should do is后面到底加ing还是to do? like后面加to do还是ing what we should do is 后面加todo 或do.为什么不能加doing The best way to...is..后面加v-ing还是to do what I want to do 后面的动词要不要接ing?还是可以加 to do? practise后面加动词ing还是to do? what should we do to water?还是 what will we do to water? what we should do is to persistence这句话对吗 what else is he thinking of 后面加 to do 还是 doing take后面加to do还是do hope 后面加to do ,还是do? it's hard to say what we should do,因为后面的what we shoud do是从句所