Question

如何判断todo做状语还是定语

Answer 1

to do是动词不定式，其用法主要是从句子意思上去判断，其次是看句子结构：
一、动词不定式可以作三大状语:
1 原因状语
主系表(心理)+to do
I am glad to see you.
2 目的状语 to do sth. ，in order to do sth. ，so as to do sth.
To get up early，he goes to bed early.
3 结果状语
too...to do sth.
...enough to do sth.
so/such...as to do sth.
only to do sth.
He arrived home only to find no one was at home.
二、动词不定式作定语放在被修饰的名词之后
1 He is the first person to get home.被修饰词person与动词不定式在意思上有主谓关系。
2 He has no time to do his homework.(同位关系)
3 He has many things to do.(动宾关系)

Answer 2

a:后位定语 I have something to do (to do 作后位定语修饰something,和something 有逻辑上的动宾关系）
He was the first person to reach the top of the mountain.( to reach the top of the mountain作后位定语修饰the first person,和the first person 有逻辑上的主谓关系）
B.目的状语
I got up early to catch the first bus.这句中的to catch the first bus是目的状语,修饰谓语got up)
He went to the raileay station to meet his friend.这句中的to meet his friend 是目的状语修饰went)
如果不定式前面可以加in order 或者so as （为了,以便） ,那肯定是目的状语