急用!指出下列句子中不定式的句子成分
1.I want to buy a new pair of shoes（　　）
2.He forgot to bring your dictionary( )
3.When did you start to learn English?( )
4.He is learning how to drive.( )
5.I haven't decided when to leave.( )
6.We went to help thr farmers with the harvest.( )
7.Let's stop to have a rest.( )
8.I'll try my best to catch up with my classmates.( )
9.I'm glad to see you.( )
10.I'm sorry to hear that.( )
11.He is too young to go to school.( )
12.He didn't work hard enough to learn English well.( )