在某个系统内单一故障或某些简单故障并不能使主注意灯和系统信号牌亮，在这种情况下，可以通过按压信号牌的方法使该故障显示出来。
参考答案：对
阅读理解。
(H---Harry, L—Lily)
H: Who's cooking over there, Lily?
L: My mother is.
H: Do you cook?
L: Yes, but I don't like to do that very much. I go to school from Monday to Friday.
H: What about your father?
L: He doesn't do any housework. He likes reading and writing.
H: Where does he work?
L: In a middle school. He teaches Grade Two English.
H: Do you have any brothers?
L: Yes. Bill is my brother.
H: Does he do any housework?
L: Hey! He's only two. He can't do anything.
1. How many people are there in Lily's family?
_____________________.
2. Who does much housework in Lily's family?
3. What's Lily's father?
4. Is Lily a worker or a student?
5. How old is Bill?
左颈总动脉起于（）
A.主动脉弓
B.头臂干
C.主动脉升部
D.主动脉胸部
E.椎动脉
