问题描述：
[单选]
There should be a lubricating oil（）between the main beatings and the crankshaft．
A．film
B．cap
C．lacquer
D．shell
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：These piston rings are so badly worn that they must be（）．
下一篇：There is an injection pump for each cylinder， which is usually operated once every cycle by（）on the camshaft．
- 我要回答: 网友(216.73.216.119)
- 热门题目: 1.锅炉循环水流速度和流量比不能 2.废气锅炉受热面废气温度不能太 3.烟灰具有粘性，这是烟灰发生沉