You are allowed one carry-on item and one personal item on most flights, and they are both subject to restrictions.
A. 大多数航空公司规定旅客禁止随身携带液态物品，行李超重另行收费。
B. 大多数航班允许随身携带一件行李和一件个人物品，大小不受限制。
C. 大多数航空公司允许你携带一件行李和个人物品，但尺寸有限制。
D. 大多数航班允许旅客随身携带一件手提行李和一件个人物品，两者都有尺寸限制。
查看答案
In the sentence “In some designs the cylinder oil is timed so that the oil injects only on the piston ring belt.” The "piston ring belt" means _____.
A. piston crown
B. piston ring groove
C. piston skirt
D. piston ring area
A diesel engine using lube oil with too high a viscosity will exhibit ____.
A. increased starting difficulty in cold weather
B. increased oil consumption
C. thickening at higher operating temperatures
D. minimal friction losses
The ability of lubricating oils to resist viscosity changes during temperature changes is indicated by the _______.
American Petroleum
B. viscosity index number
C. Seconds Saybolt Furol number
D. Seconds Saybolt Universal number
The function of lubricating oil is to ___.
A. reduce friction between moving surfaces
B. provide even distribution of bearing wear
C. reduce the accumulation of harmful detergents
D. maintain a constant oil temperature output at each bearing
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