钻铤的壁厚是钻杆壁厚的（）。
A.4~6倍
B.7~8倍
C.2～3倍
D.7.5~8.5倍
参考答案：A
Neither side is prepared to talk to _____ unless we can smooth things over between them. [ ]
A. others
B. the other
C. another
D. one other
人行斜道的宽度和坡度的规定是（）。
A.不宜小于1m和宜采用1：8
B.不宜小于0.8m和宜采用1：6
C.不宜小于1m和宜采用1：3
C.不宜小于1.5m和宜采用l：7
