单项选择题 Horizontal subdivision decks forming watertight compartments in the columns of a semisubmersible ship increase the unit’s（）.

单项选择题 High pressure and low pressure alarms must be tested（）.

单项选择题 High clouds，composed of small white flakes or scaly globular masses，and often banded together to form a “mackerel sky”，would be classified as（）.