外伤性截瘫病人，建立反射性膀胱的护理措施是()。

A．留置导尿，定时开放引流

B．每周更换导尿管

C．每2小时更换体位

D．抬高床头，多饮开水

E．每日膀胱冲洗1次

When two vessels are in immediate danger of collision，the stand-on vessel must（）.

A.abandon ship

B.assist in taking whatever action is necessary to avoid collision

C.hold course and speed

D.sound a distress signal