你可能感興趣的試題

A tank which has been sealed for a long period of time can be dangerous because （）.

A.steel surfaces consume oxygen by rusting
B.sealed tanks usually form a vacuum
C.moisture condenses in the tank, displacing the oxygen
D.most tank coatings give off poisonous vapors in the presence of moisture

單項(xiàng)選擇題

Records of garbage disposal are required to be maintained （）.

A.until each quadrennial PSC inspection
B.until the end of each voyage
C.for a minimum of one year
D.for a minimum of two years