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【单选题】据《扬子晚报》2004年6月6日报道：渤海的污染已到了临界点，如果再不采取果断措施遏止污染，渤海将在10年后变成“死海”．据资料称，渤海每年收纳的污水高达28亿吨，每年收纳的污染物超过70亿吨；海底泥中，重金属超过国家标准的2000倍；由于渔民滥捕和水质污染，渤海特有的黄花鱼、鲈鱼、比目鱼、鱿鱼、铁茄蟹、蛤蜊等特色水产的产量已大大降低，如今渤海没有一种鱼类、贝类、螃蟹能够形成规模群带．根据以上材料...
A.
维生素
B.
蛋白质
C.
淀粉
D.
葡萄糖
【单选题】Passage Four Initial voyages into space introduced questions scientists had never before considered. Could an astronaut swallow food in zero gravity To keep things simple, astronauts on the Project ...
A.
was an unusual problem among astronauts
B.
was what puzzled the early scientists
C.
caused new problems in space flights
D.
drew the attention of the general public