问题描述：
[单选]
These piston rings are so badly worn that they must be（）．
A．renewed
B．welded
C．machined
D．chromium-plated
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：They understand the（）of automatic sludge discharging of the purifierBut they are not good in practice．
下一篇：There should be a lubricating oil（）between the main beatings and the crankshaft．
- 我要回答: 网友(216.73.216.223)
- 热门题目: 1.曲轴臂距差对应着曲柄的变形， 2.中国船级社允许船舶曲轴臂距差 3.测量曲轴臂距差后，应对所测数