How long do you think it will be _____man can finally solve the problem of cancer?——Well．it depends

I’m not quite sure how to get there-I’d better __________ a map.

What’s your dream job, David-I like music, and l want to be a great____ like Lang Lang.

____ I met Nelson Mandela was a very difficult period of my life.

hool owns many qualified teachers,but when it_____________facilities, the school is not modern enough