问题描述：
[单选]
The projection on a shaft designed to change circular motion into up and down or back and fore motion is called（）．
A．wheel
B．crankshaft
C．running gear
D．cam
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：The pump has a constant stroke and the amount of fuel delivered is regulated by rotating（）which has a specially arranged helical groove cut into it．
下一篇：The process to remove exhaust gases by blowing in fresh air is called（）．
- 我要回答: 网友(216.73.216.127)
- 热门题目: 1.使废气锅炉出口排烟温度t2， 2.与废气锅炉蒸发量D有正确关系 3.推进装置的推进效率为推进轴上