英语选择题The colorless gas---we cannot live is called oxygen

选A.
此题勉强称得上一个定语从句,当然老师在讲的时候还有个更详细的名字,但这些都不重要,做对题才是硬道理,不是么?“___without which”在整个句子中做gas的定语即修饰gas,这句话的主谓宾形式是The gas is called oxygen.扩展之后为The colorless gas（we cannot liveAwithout which ）is called oxygen.即这种无色的气体（离开了它我们就无法生存）被称作氧气!