单项选择题
A.become due
B.become valid
C.become lawful
D.become effective
单项选择题 If your vessel is equipped with a radiotelephone，what must also be aboard? （）
单项选择题 If your passenger vessel has been issued a stability letter，it must be （）.
单项选择题 An International Tonnage Certificate will be issued to a vessel when it meets several requirements，one of which is that the vessel must （）.