问题描述：
[单选]
The film of oil between the rings and the liner is not only essential for the lubrication but also（）achieving a gas seal．
A．play a great part on
B．run a role in
C．plays an important part in
D．acts as important part at
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 fine filters will be arranged（）one can be cleaned while the other is operating．
下一篇：The figure that the volume of air at BDC is divided by the volume of air at TDC is termed as（）．
- 我要回答: 网友(18.188.93.255)
- 热门题目: 1.影响船舶动力装置可靠性的设计 2.大量产品的故障率随时间变化的 3.由于船舶的特殊性，使动力装置