题目

某无色气体可能由 H2、CH4、CO、CO2 中的几种组成。将混合气体通过澄清石灰水，出现白色浑浊；将剩余气体导出，经干燥后点燃，罩在火焰上方的干燥烧杯内壁有水珠生成。该混合气体的可能组成是（ ）A.H2、CH4 B.H2、CO C.CO2、CO D.CH4、CO、CO2 答案：A group of swans flew down to a beach where a crow (乌鸦) was jumping around. The crow watched them with disdain (笔试).“You have no flying skills at all!” he said to the swans. “All you can do is to move your wings. Can you turn over in the air? No, that’s beyond you. Let’s have a flying competition. I’ll show you what real flying is!”One of the swans, a strong young male, took up the challenge (挑战). The crow flew up and began to show his skills. He flew in circles, performed other flying tricks, and then came down and looked proudly at the swan.Now it was the swan’s turn. He flew up, and began flying over the sea. The crow flew after him, making all kinds of comments (评价) about his flying. They flew on and on till they couldn’t see the land and there was nothing but water on all sides. The crow was making fewer and fewer comments. He was now so exhausted that he found it hard to stay in the air, and had to struggle to keep himself from falling into the water.The swan pretended (假装) not to notice, and said, “Why do you keep touching the water, brother? Is that another trick? “ “No,” said the crow. He knew he had lost the competition. “I’m in trouble because of my pride (自大) ! If you don’t help me, I’ll lose my life...” The swan took pity on him, and took him on his shoulders and flew back to the beach.【小题1】 What’s the correct order of the following events?a. The crow followed the swan and got into trouble. b. The swan felt pity for the crow and saved it.c. The crow had to ask the swan for help.d. The swan accepted a challenge of performing flying tricks.A．a, d, b, cB．a, b, d, cC．d, a, c, bD．d, c, a, b【小题2】What does the underlined word “exhausted” in Paragraph 4 mean?A．Tired.B．Bored.C．Nervous.D．Frightened.【小题3】What do we learn from the passage?A．Practice makes perfect.B．The early bird catches the worm.C．No pains, no gains.D．Pride goes before a fall.