请问动词不定式为什么不能做谓语？请举例？多谢！

动词不定式是非谓语动词,所以不能单独做谓语.可以和be 动词一起构成谓语.
如,My job is to feed the animals .
is to feed the animals 系表结构就是句子的谓语.

不能
动词不定式为非谓语动词形式
只能做主语 To read in the sun is bad for your eyes.
宾语 I want to go shopping.
定语 I want something to eat.
状语They went there to have fun.
I want to learn English well. 这句话中的to learn 是宾语!