以下各项，哪种顶板离煤层最远？（）
A.伪顶
B.直接顶
C.间接底
D.老顶
参考答案：D
______ is known to us is that tobacco contains nicotine and other harmful products, so you should
give up smoking.?[ ]
A. As
B. It
C. What
D. Which
《纪律条令》
