A.poor B.bad C.fair D.good
单项选择题LAND-BASED AUTHORITY CONDUCTING AND CO-ORDINATING SEARCH AND RESCUE OPERATIONS IN A DESIGNATED AREA defines（）.
A.RCC B.OSC C.CSS D.GPS
单项选择题When my ship arrived there，their ship（）.
A.has left already B.left already C.had left already D.would left already
