9. She asked me why she had to conduct that research. 

S + asked (O) + What/When/Why… + S+V(lùi thì)

10. It is necessary for him to talk to a psychologist abput his current situation.

It is necessary (+ for somebody) + to do something

11. Latin used to be an international language. 

S + used to be + N

=>
9. She asked me why she had to conduct that research.
-> câu tường thuật dạng WH questions : asked sb + từ để hỏi + S V(lùi thì, have to -> had to/ this -> that)
10. It is neccessary for him to tallk to psychologist about his current situation.
-> It's necessary (for sb) to V ~ need to V
11. Latin used to be an international language.
-> used to V : đã từng