单项选择题
The crank pin journal is provided with large bores for （）.
A.lubrication B.cooling C.balancing purpose D.ventilation
单项选择题 The crank chamber oil （）.
单项选择题 The correct tightening is obtained by use of （） to measure the extension given to the bolts.
单项选择题 The cooling water temperature （） over a period of 8 hours, and then shut down.
