从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
( )1. —The charity walk begins _______ 9.00 a.m. Don’t be late.
—No problem.
A. in B. at C. on D. to
( )2.--- Must I go to Beijing tomorrow?---- No, you .
A. mustn’t B. can’t C. must D. needn’t
( )3. I wanted to buy a new MP4 but there were left at the shopping mall.
A. no one B. nothing C. anyone D. none
( )4. It’s very clever you to learn more from others.
A. about B. with C. for D. of
