Question

we should do _____ we can _____ the cultural sites

we should do _____ we can _____ the cultural sites
A what,protect
B what,to protect```
答案是选B的``为什么诶？

Answer 1

完整的句子应是： We should do what we can do to protect the cultural sites
这里的动词不定式 to protect是做目的状语

Answer 2

不定式表目的

Answer 3

to的动词不定式用法：
do something to do someting
后面接带to的动词不定式，表示目的