On my ______ birthday, I got a guitar as a gift from my father.
----How old are you? ----I’m fifteen. I was born ________ 1990.
I study for a test _________ working with a group.
A tsunami(海啸) happened in some southern Asian countries________ December, 2004.
Tim’s mum is worried _______ her son’s eyesight as he plays online games too much.
We should return the books to the library ______ time.