小明从化学方程式2H2O2
2H2O+O2↑中总结的信息有：①参加反应的物质是水和氧气；②反应能在常温下进行；③反应前后原子的总数不变；④反应前后物质的种类不变；⑤二氧化锰是催化剂，其质量和性质在化学反应前后不变；⑥每68份的过氧化氢完全反应后，能生成36份的水和32份的氧气。其中正确的是[ ]
A．②③⑥
B．②④⑤⑥
C．①③④⑥
D．②③④
答案：A
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| We 1 a survey about different 2 transportation last week. We asked students 3 their favorite kinds of transportation. 4 are some of the results. Most students come to school 5 bike and they like 6 bikes. Of course, bikes are 7 than cars and buses. Some students like cars 8 they are safer than bikes. Cars are also faster than bikes and buses. Among some students, buses are not popular, because they often have 9 passengers (旅客). Buses are also dirtier and more crowded (拥挤). However (然而), not many people 10 afford (买得起) a car. |
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