题目

下列关于氧气的说法正确的是（ ）A. 氧气可以充入灯泡做保护气 B. 氧气可以作燃料C. 氧气可以用于潜水 D. 氧气可以与所有物质发生化学反应 答案：【答案】C【解析】A、氧气化学性质较活泼，不能用作保护气，选项错误；B、氧气具有助燃性，不具有可燃性，不能用作燃料，选项错误；C、氧气能供给呼吸，故可用于潜水，选项正确；D、不是所有物质均能和氧气发生化学反应，选项错误。故本题选C。完形填空（共10小题；每小题1分，满分10分）阅读下面短文，从短文所给各题的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。On the first day of school our teacher introduced someone we didn’t know. I stood up to look around when a 1 hand touched my shoulder.I turned around to 2 a little old lady with a warm smile. She said, ＂Hi, handsome. My name is Rose. I’m eighty-seven years old.＂＂Why are you in university at such a YOUNG age?＂ I asked. She 3 ,＂I’m here to meet a rich husband, get married, have a couple of kids, and then retire and travel.＂I knew she was joking. I was curious(好奇的) what might have encouraged her to be taking on this 4 at her age.＂I always dreamed of having a university 5 and now I’m getting one!＂ she told me. We became friends. Every day we would talk nonstop after class. I always enjoyed listening to this ＂time machine＂ as she 6 her wisdom and experience with me. And Rose 7 made friends wherever she went. At the end of the 8 , we invited Rose to make a little speech. She cleared her throat and 9 ,＂We do not stop playing because we are old; we grow old because we stop playing. I’ve learned a few secrets to staying young, being happy, and achieving success. You have to laugh and find humor every day. You’ve got to have a dream. 10 you lose your dreams, you will die.＂＂There is a huge difference between growing older and growing up. Anybody can grow older. That doesn’t take any talent or ability. The idea is to grow up by always finding the opportunity in change.＂ 【1】 A. gentle B. empty C. smooth D. clean【2】 A. miss B. find C. feel D. mention【3】 A. expressed B. shouted C. replied D. repeated【4】 A. choice B. chance C. change D. challenge【5】 A. education B. career C. culture D. job【6】 A. recorded B. discussed C. shared D. explained【7】 A. suddenly B. easily C. politely D. slowly 【8】 A. meeting B. month C. discussion D. term 【9】 A. began B. hoped C. smiled D. ended【10】 A. Though B. When C. Because D. Before