第四章单元测试
- An average air/fuel ratio for good combustion is about ( ) by weight.
- A valve consists of a( )and ( )stem. （ ）
- The ( )provides the force necessary to close the valve and hold it tightly against its seat.
- The inlet valve is opened before TDC and closed after BDC.（ ）
- Camshaft's function is to deliver spark positively and timely in a definite sequence. （ ）
A:13:1
B:20:1
C:18:1
D:15:1
答案:15:1
A:tappet
B:stem
C:rocker
D:head
A:tappet
B:valve
C:valve spring
D:rod
A:错 B:对
A:错 B:对
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