问题
选择题
常温下，在密闭容器里分别充入两种气体各0.1mol，在一定条件下充分反应后，恢复到原温度时，压强降低为开始时的1/4。则原混合气体可能是 [ ]
A．H2和O2
B．HCl和NH3
C．H2和Cl2
D．CO和O2
答案
答案：A
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常温下，在密闭容器里分别充入两种气体各0.1mol，在一定条件下充分反应后，恢复到原温度时，压强降低为开始时的1/4。则原混合气体可能是 [ ]
A．H2和O2
B．HCl和NH3
C．H2和Cl2
D．CO和O2
答案：A
During the day we work and play, and at night we sleep. Our bodies rest while we are 1 . In the morning we are ready 2 again. Our bodies grow 3 while we are asleep. Children who are tired usually 4 sleep. We can get better at our lessons 5 we have had plenty of rest. Boys and girls who are eight or nine years old need ten 6 sleep every night. Our bodies need plenty of 7 when we sleep. If we do not get enough fresh air, we 8 tired when we wake up. While in bed we must not cover our 9 . Our lungs(肺) needs to get 10 fresh air. If we 11 our windows at night, we can have plenty of fresh air. Cool air is better than warm air. Boys and girls who want to be 12 must get plenty of sleep. Also, we need some after-school activities to keep in good health. 13 _students run every day. Some boys play basketball 14 a week. 15 girls, some often play volleyball….So good sleep and exercise can help us grow better and study better.
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