汽车每行驶（）km或夏季行驶5-6天（冬季行驶10—15天）应检查蓄电池放电程度一次。
A．1000；
B．3000；
C．5000
参考答案：A
I ________ asleep because it took me a long time to realize that the telephone was ringing.
A．could fall
B．need have fallen
C．must have fallen
D．may fall
整个咽喉道岔都扳不动，如何处理？
