题干
四冲程内燃机工作时，将机械能转化成内能的冲程是（ ）
A：吸气冲程
B：压缩冲程
C：做功冲程
D：排气冲程
答案(点此获取答案解析）
B
at 6:30 in the morning. I 
at home. Then I 
at 7:10. I
at 7:30. I 
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or 
. I
at 9:00. This is my day.
