单项选择题
A.becomes null and void
B.remains effective
C.is to be extended
D.is to renewed
单项选择题 Maritime Declaration of Health is to be rendered to () by the master of ship arriving from port outside the territory.
单项选择题 Masters of ocean-going ships must keep in mind that () should be hoisted immediately if any quarantinable diseases be found.
单项选择题 I shall apply () the extension of my Deratization Certificate.