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参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】In many places water is becoming scarcer. Treating it as a right makes the scarcity worse. Ideally, efficient water use would be encouraged by charging for it, but attempts to do so have mostly proved...
A.
People should only be entitled to certain amount of water free.
B.
People can borrow water from their neighbors when necessary.
C.
People are free to bargain for water in market in their daily lives.
D.
People have the right to trade water to raise water productivity.
【单选题】目前世界上已证明达菲是能治疗禽流感的唯一良方．莽草酸（C7H10O5）是生产达菲的原料之一，下列关于莽草酸的说法错误的是（ ）
A.
相对分子质量为174
B.
碳元素质量分数大于氧元素质量分数
C.
莽草酸中有7个碳原子、10个氢原子、5个氧原子
D.
莽草酸中C、H、O元素的质量比为84：10：80