题目

在氧气、氢气、一氧化碳、二氧化碳、氮气、甲烷六种气体中：（填化学式） （1）在空气中所占体积分数最大的是             ； （2）相同条件下，密度最小的是                 ； （3）有剧毒，又能作为还原剂的是               ； （4）燃烧时可生成两种产物的是                 ； （5）可使紫色石蕊试液变红色的是               ； （6）可用于炼钢的是（化合物）              ； （7）在一定条完形填空(每空1分，共10分)Many of you are studying English and you may be     why it is so difficult to learn. It’s actually not too difficult to learn        you know some      about the language and culture that it reflects (反映). Perhaps the first thing you need to know about English is that it is made up of several other languages         French, German, Latin, Greek and Anglo-Saxon. In addition, there are words      Spanish in English and many American Indian words and names, even some Chinese and Japanese     can be found in the English language. This borrowing of words      other languages is      of the key reasons     some of the difficulties that people meet with (遇到)      they are learning English.【小题1】 A．knowing B．wondering C．earning D．hearing  【小题2】 A．but B．and C．if D．unless  【小题3】 A．news B．facts C．truth D．information  【小题4】 A．such as B．the same as C．so as D．for example  【小题5】 A．in B．off C．of D．from  【小题6】 A．words B．culture C．language D．letters  【小题7】 A．for B．to C．from D．out  【小题8】 A．that B．something C．one D．this  【小题9】 A．why B．if C．what D．for  【小题10】 A．when B．before C．after D．while