I really don’t know .A. where to travel toB. how to solveC. what to do itD. who to talk to

I really don’t know .
A. where to travel to
B. how to solve
C. what to do it
D. who to talk to

A. where to travel toB. how to solveC. what to do it(答案→)D. who to talk to解析：what、who、that是关联代词，他们本身可以做主语或者宾语；where、how、when是关联副词，做状语，不能做宾语或者主语。做这类题目 要看后面的动词是否是及物动词，或者是否有介词，如果是及物动词或者有介词，那么就是用what、who，如没有就用where、how、when。此题：A.travel to 中有介词to，因此不能和where连用；B.solve是及物动词，不能和副词how连用；C. do是及物动词，但是后面已经有it作宾语了，再用what就重复了；D. talk to中有介词to，who做to的宾语，故选D 正确。

我明天再问问老师，叫他解释下这个问题