1．She told me that happiness lies ________ helping others.
[答案] in
2．He talks about Rome as if he ________(be) there before.
[答案] had been
3．The man hurriedly returned home, only ________(find) he had left his key in the office.
[答案] to find
4．I'm ________(terrify) to think about the fact that my mother will die some day.
[答案] terrified
