old tom thinks helping others is to help himself.old tom 是主语
3个回答

追问的问题:

一个句子中只能出现一个动词做谓语,若出现第二动词则需要用动词的变换形式(作为非谓语),有三种:

(1)to do 表将来或目的 eg. I want to be a teacher.

(2)doing 表进行、状态 eg. The man talking loudly is Mr Green.

(3)done 表被动、完成 eg. Well, the rice is almost done!

How would you like your steak done?

动词只能做谓语,而动词的三种变换形式即非谓语可以做除谓语之外的其他成分,也就是你所说的“.语”