问题描述：
[单选]
Lubricating oil should be changed on a heavy duty diesel engine when（）．
A．it gets dark in color
B．a sample rubbed between fingers feels thin
C．it has been in use for a specified interval
D．it no longer supports combustio
参考答案：查看无
答案解析：无
☆收藏
答案解析：无
☆收藏
上一篇：Maintaining the close tolerances in diesel fuel pumps and injectors requires the use of（）．
下一篇：If your propeller is racing in rough weather，you should（）．
- 我要回答: 网友(216.73.216.96)
- 热门题目: 1.在早期故障内故障率比较（）， 2.F（r）直接反映出故障随（） 3.可靠性着重研究的是（）。