汽车电源系统主要由什么组成？
参考答案：
主要由蓄电池、交流发电机、电压调节器等组成。
用适当的介词填一填。
1. A postcard has a picture __________ it.
2. Please send the postcard __________ Li Ming __________ Thursday.
3. I have a picture __________ my family.
4. Danny sits down __________ Jenny's left.
为什么说效益是公安决策的灵魂和核心？
