1 I'd like (to help homeless people).
我想帮助无家可归的人.
不定式做宾语.
2.The girl could visit the sick kids in the hospital (to cheer them up).
这个女孩看望生病的孩子,让他们开心起来.
不定式做目的状语.
3.Mario believes it can help him (to get his future dream job).
马里奥相信它能帮它获得将来的理想工作.
不定式做宾语补足语.
4.It's very important (to keep healthy).
保持健康很重要.
不定式是真正的主语,it是形式主语.
5.Her job is (to look after the children).
她的工作是照看孩子们.
不定式是作表语.