控制部分与受控部分间的双向信息联系称为
A.K+外流B.Ca2+内流和K+外流C.Na+内流D.Ca2+缓慢内流E.Na+和Ca2+内流
参考答案:C
车流对向行驶时,时速超过( )时,必须设置中央隔离带。
A.40km/hB.50km/hC.60km/hD.70km/h
A man was sighted as he fell overboard. After completing a Williamson turn,the man is not sighted. What type of search should be conducted?()
A.Expanding circle
B.Sector search
C.Parallel track pattern
D.Datum-drift search