驾驶机动车在有这种标志的路口怎样通过最安全？（）
A．停车观察路口情况
B．加速尽快进入路口
C．减速观察左后方情况
D．减速缓慢进入路口
参考答案：D
补全对话(每空一句)。
(At Mr.White's office in a middle school )
A: Hello!__1_ ?
B: Speaking, please.?
A: I'm Peter's mother.I'd like to ask for my son.
B: __2_ ?
A: He doesn't feel well this morning.He has a cold.
B: __3_ . Is it serious?
A: Not very serious.But the doctor asked him to stay in bed and have a good rest.
B: Don't worry. __4_ .
A: Thank you, sir. Goodbye!
B: __5_ !
X线量正比于（）
A.管电压值
B.曝光时间
C.焦-片距
D.物体-胶片距
E.以上都不是
