单项选择题
An illness preferably of an infectious nature seizin more than two persons on board at the same time defines（）.
A.disease of crew B.crew illness C.group illness D.mass disease
单项选择题 Areas which cannot be scanned by the radar of the vessel because they are shielded by parts of its superstructure, masts,etc means（）.
单项选择题 Compatibility of goods states（）.
单项选择题 Course directed by the 0SC or CSS to be steered at the beginning of a search is（）.
