----How old are you?
----I’m fifteen. I was born ________ 1990.
| A．in | B．at | C．on | D．for |
I study for a test _________ working with a group.
| A．in | B．by | C．at | D．to |
A tsunami(海啸) happened in some southern Asian countries________ December, 2004.
| A．at | B．on | C．in | D．by |
Tim’s mum is worried _______ her son’s eyesight as he plays online games too much.
| A．for | B．about | C．with | D．of |
We should return the books to the library ______ time.
| A．about | B．on | C．by | D．for |