题目

一定温度下，在2L密闭容器中发生反应：2N2O5(g) 4NO2(g)+O2(g)ΔH>0.已知N2O5物质的量变化为图中曲线b。下列说法中正确的是（） A . 0~20s内平均反应速率v(N2O5)=0.1mol·(L·s)-1 B . 10s时，正、逆反应速率相等，达到平衡 C . 20s时，正反应速率大于逆反应速率 D . 曲线a可表示NO2的物质的量随反应时间的变化 答案：D One day, there was a blind man called John sitting on the bench with a hat by his feet and a sign that read, "I am blind. Please help me. "A creative publicist( 广告员) named Tom was walking by the blind man and stopped to see that the man only had a few coins in his hat. He put a few of his own coins in the hat. Without asking for permission（许可）, he took the sign, turned it around and wrote a new message. Then he put the sign by the feet of the blind man, and left.Later that afternoon the publicist returned to the blind man and noticed that his hat was almost full of bills and coins. The blind man recognized(识别) his footsteps and asked if it was he who had changed his sign. He also wanted to know what the man wrote on it. The publicist said, "I just wrote the message a little differently. " He smiled and went on his way.The new sign read, “ Spring has come, but I can't see anything. “1.What's the blind man's name?A. Tom. B. John. C. Tony. D. Sorry, I don't know.2.Who wrote a new message?A. The blind man. B. The teacher. C. The publicist . D. The farmer.3. How did the blind man recognize the publicist?A. By his sign. B. By his footsteps. C. By his voice. D. By his coins.4.When did the story happen?A. In spring. B. In summer. C. In autumn~ D. In winter.5.What can we learn from the passage?A. Publicists are always friendly and helpful.B. We can get more money by changing a sign.C. The blind man is very stupid, so he has little money.D. The power(力量) of language is great