【单选题】
It is dangerous for vessels without the operational radar（）the estuary.
A、to get
B、to approach
C、to proceed
D、to close
查看正确答案
A、A.In times of heavy weather, it is extremely dangerous if a seaman is not enough tall B、B.In times of heavy weather, it is extremely dangerous if a crew is very short C、C.In case of bad weather, it is particularly dangerous if there is a shortage in personnel D、D.In case of bad weather, it is particularly dangerous if there are enough personnel
