挖掘机装车时（）勺斗从汽车驾驶室上越过。
A、可以
B、不得
C、严禁
参考答案：C
You should try to write ____ even when you're busy. As you know, practice makes perfect. [ ]
A. now and then
B. more or less
C. sooner or later
D. here and there
下列不属于摩氏硬度计矿物的是（）。
A.石英
B.滑石
C.橄榄石
D.磷灰石
