题目

下列电离方程式书写正确的是（） A . CaCl2＝Ca2++ B . HNO3 H++ C . NaHCO3＝Na++H++ D . NaClO＝Na++ClO－ 答案：DShortly after the war, my brother and I were invited to spend a few days with an uncle who had just returned from abroad. He had rented a cottage in the country, although he rarely spent much time there. We understood the reason for this after our arrival: the cottage had no comfortable furniture in it, many of the windows were broken and the roof leaked, making the whole house damp.On our first evening, we sat around the fire after supper listening to the stories which our uncle had to tell of his many adventures in distant countries. I was so tired after the long train journey that I would have preferred to go to bed; but I could not bear to miss any of my uncle’s exciting tales.He was just in the middle of describing a rather terrifying experience he had once had when there was a loud crash from the bedroom above, the one where my brother and I were going to sleep.“It sounds as if the roof has fallen in!” cried out my uncle, with a loud laugh.When we got to the top of the stairs and opened the bedroom door, we could see nothing at first because of the thick clouds of dust which filled the room. When the dust began to clear, a strange sight met our eyes. A large part of the ceiling had fallen down, falling right on to the pillow of my bed. I was glad that I had stayed up late to listen to my uncle’s stories, otherwise I should certainly have been seriously injured, perhaps killed.That night we all slept on the floor in the sitting room downstairs, not wishing to risk our lives by sleeping under a roof which might at any moment fall down on our heads. We left for London the very next morning and my uncle gave up his cottage in the country. This was not the kind of adventure he cared for either!1.Why did the uncle seldom spend much time in the country cottage?A. Because the roof of the cottage was falling.B. Because the cottage was in bad condition.C. Because he was used to living abroad.D. Because there was no furniture in it.2.When they opened the bedroom door, they could see nothing at first because __________.A. it was completely dark insideB. there was too much dust in the airC. something strange blinded themD. it was too bright inside3.The writer felt glad that he had stayed up late because __________.A. he did not miss the exciting storiesB. he spent more time with his uncleC. he had a lucky escapeD. he saw a strange sight4.Which of the following can best describe the writer’s uncle?A. Adventurous and good at storytelling.B. Humorous and good at making jokes.C. Dependable and generous with moneyD. Considerate and sensitive to danger.