件数栏应填 ______ 。
A．100000
B．50000
C．6000
D．6200
参考答案：D
计算：6a6÷3a3＝________．
—Have a cigarette, will you ?
—No, thanks. I _________ heavily, but I’ve given it up recently.
A．am used to smoking
B．used to smoking
C．used to smoke
D．has used to smoke
