What should you do if you have transmitted a distress call a number of times on channel 16 and have received no reply?（）

A.Repeat the message using any other channel on which you might attract attention

B.Key the microphone several times before transmitting again

C.Turn up the volume on the receiver before transmitting again

D.Report the problem to the head electrician

高血压病第三期临床表现为

A．舒张压持续在13.3kpa(100mmhg)以上
B．心电图示左心室肥大
C．眼底动脉狭窄
D．脑出血
E．蛋白尿