7、ythingare(4)blueandgreen.Duringtheday,thereisenough lights(5)fortoseethingsinthewater.Whenfishswimnearby,youcancatchthemby(6)yourhands. Whenyouhavetanksofaironyourback,youcanstayindeeply(7)waterforalongtime.So(8) you mustbecarefulwhenyoudivedeepwater.:4:单项选择题Arep