I don’t think ______ 18-year-old boy is serious enough to drive.

Shanghai is a beautiful city. Do you think so? —Yes, I _______ there last year and fell in love with it.

How old is Mary? —She’s fifteen. She was born _______ 1994. [ ]

I’m sorry to keep you ______ for an hour. Now let’s begin our work.

I often listen to the news _______ the radio. [ ]