Is this school _____ you visited last year?
We ________the difficulty together, but why didn’t you tell me?
He gave the old couple a lot of money and didn’t expect to receive anything ______for them.
The math problem seems very easy, but in fact it is very difficult_______.
-----What did you think of Mount Tai? ------Wonderful. It’s worth ______once again.
In the past twenty years, the sad father has been to many places-______his lost son.