99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項(xiàng)選擇題

Lifeboat launching is operated at intervals of （）months.

A.one
B.two
C.three
D.four

你可能感興趣的試題

單項(xiàng)選擇題

Fire drill is carried out once a （）.

A.year
B.day
C.week
D.month

單項(xiàng)選擇題

Any emergency pump situated （）machinery space should also be started.

A.outside
B.under
C.beside
D.besides