单项选择题 When（）clean ballast water from any vessel，an application shall be made to Harbor Authorities for approval.

单项选择题 When checking the oxygen content of the cargo tanks prior to loading cargoes requiring vapor recovery，the atmosphere must be sampled（）.

单项选择题 When a cargo boom or crane is rated at varying capacities，there will be a table at the controls which relates safe working load to（）.