单项选择题
I can’t take part in the party tonight because I have to（）my little sister.
A.look forB.look afterC.look upD.look down upon
单项选择题 You know （）about it than Tom does．
单项选择题 The factory was closed down as a （）of the terribly bad management．
单项选择题 Someone is ringing the doorbell．Goand see（）．
