钢轨探伤仪为及时发现某通道有反射回波或底波丢失，各个探头的报警声音应有所（）。
参考答案：区别
六腑
Woman: My headache is killing me. I thought it was going away, but now it is getting worse and worse. Man: I told you yesterday to make an appointment. Question: What does the man mean().
A. The woman has been complaining too much.
B. The woman’s headache will go away by itself.
C. The woman should have seen the doctor earlier.
D. The woman should confirm her appointment with the doctor.
