I haven't decided which train I should take.(用动词不定式改写句子)顺便解释一下什么是动词不定式

问题描述:

I haven't decided which train I should take.(用动词不定式改写句子)
顺便解释一下什么是动词不定式

I haven't decided which train to take .
to do sth这个结构就是不定试

I haven't decided which train to take.
动词不定式简单说就是在动词前加to,少数情况不加

i haven't decided which train to take.
动词不定式是to do,to be done,to be doing等结构