煤矿井下作业地点经常受到（）有毒有害气体和破碎顶板的影响。
A、水
B、火
C、瓦斯
D、矿尘
E光照不足
参考答案：A, B, C, D
— Can I come and see it this afternoon?
— ______[ ]
A. Sure, come over about two.
B. Not at all.
C. I'm sorry, I can't go today.
D. You're welcome.
下面四个选项中，哪一项能由右边给定的图形的规律演变而成（）
A．
B．
C．
D．
