外壳内陷，可能的原因是：（）
A、放电后未补充电
B、电池开路放臵时间长且气温低
C、壳体接触有机溶
D、环境温度过高
参考答案：A, B, C
根据汉语提示补全句子。
1. I want to go to Guilin on my ____________ (旅行).
2. There are about ____________ ____________ (三千) books in our library.
3. Which one is ____________ (更快) , bus or train? I think train is.
4. ____________ ____________ (多远) is it from hospital to your school? Three kilometres.
5. When does your bus ____________ (到达)? At about 6: 00 in the morning tomorrow.
当（）中任一条件满足时，机组的汽机跳闸连锁保护将动作停机。
A.DEH后备超速保护动作
B.DEH转速达107～111%额定转速
C.DEH系统电源故障
D.MFT动作
