12. Generalemergency alarm means a sound signal of seven short blasts and one _____ blast given with the vessel’s sound system.
(A). big
(B). short
(C). enforce
(D). prolonged
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統計: A(0), B(1), C(0), D(4), E(0) #1242526
統計: A(0), B(1), C(0), D(4), E(0) #1242526