跟刀架主要用来车削细长轴和（）。
A.蜗杆
B.阶台轴
C.曲轴
D.长丝杠
参考答案：D
停炉时对原煤仓煤位和粉仓粉位有何规定？为什么要这样规定？
American Indian languages, which differ widely, tended to group many units of meaning into multisyllabic words.
A．all tend
B．and tend
C．to tend
D．tending
