问题
选择题
空气中体积分数约为78%的气体是（ ）
A．氧气
B．氮气
C．氢气
D．二氧化碳
答案
A、氧气占21%，故选项错误；
B、氮气占78%，故选项正确；
C、空气中没有氢气，故选项错误；
D、二氧化碳占0.03%，故选项错误；
故选B
搜题请搜索小程序“爱下问搜题”
空气中体积分数约为78%的气体是（ ）
A．氧气
B．氮气
C．氢气
D．二氧化碳
A、氧气占21%，故选项错误；
B、氮气占78%，故选项正确；
C、空气中没有氢气，故选项错误；
D、二氧化碳占0.03%，故选项错误；
故选B
I’m taking my family to Europe to have a trip. My wife (妻子) and our two children are 1 going along. My brother is 2 to go with us for vacation. Because he 3 went to other countries, he is even more 4 than the children. He can’t wait to go. My father would like to stay at home, but we’ll send him postcards 5 Europe. We’re 6 next Friday. We’re going to New York by train, 7 taking a ship to Europe. When we 8 in Europe, we are going to 9 countries for sightseeing. We’re going to those places by train or by bus and we’re 10 a week there. Then we are flying home.
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