单项选择题
A spark arrestor（）.
A.keeps sparks from falling into an open tank B.secures covers on ullage openings C.prevents sparks from getting out of an enging's exhaust system D.grounds static electicity
单项选择题 A stay is（）.
单项选择题 A survival craft being used to pick up a person who has fallen overboard from a vessel ahould approach the person（）.
单项选择题 A twin screw craft being used to pick up a person who has fallen overboard from a vessel should approach if you（）.
