问题
选择题
下列方法中能鉴别出空气、氧气、二氧化碳三瓶无色气体的是[ ]
A．用蘸有澄清石灰水的烧杯
B．闻气体的气味
C．分别将燃着的小木条伸入三瓶气体中
D．观察气体的颜色
答案
答案：C
搜题请搜索小程序“爱下问搜题”
下列方法中能鉴别出空气、氧气、二氧化碳三瓶无色气体的是[ ]
A．用蘸有澄清石灰水的烧杯
B．闻气体的气味
C．分别将燃着的小木条伸入三瓶气体中
D．观察气体的颜色
答案：C
| 完型填空。 | ||||
| I was always complaining about wind or rain. 1 it was nothing unusual for the arrival of wind or rain, it caused inconvenience for me to go out, and sometimes it even created an awful atmosphere, so I 2 it strongly. On a rainy day a meteorologist(气象学家)I met was very 3 at my great anger caused by rain that made a little inconvenience for me. He asked, "Have you ever seen typhoon? Do you know what would happen to the world if there were no typhoon?" I shook my head. I had no 4 of how overwhelming it was when it 5 everything away in its way. "Well, let me tell you," the meteorologist said. "Without it the 6 of fresh water will be more serious, for it is a great 7 of water supply on earth, Without it, there would be a greater imbalance in the distribution of 8 . The equatorial area that receives the most sunshine on earth 9 entirely on typhoon to disperse (驱散)heat. Without typhoon the tropics would be even 10 while the frigid zones much colder. As a result the temperate zones would 11 from the world..." Ignorance made me 12 . I disliked wind only because it ruffled(吹乱)my hair. I hated rain merely because I had to carry an umbrella. But I had no idea at all that typhoon-something much more violent, something a thousand times more 13 than wind or rain-was a 14 to the existence of mankind. 15 no road on earth goes all the way on level ground, there's no person in the world who can do whatever he pleases. 16 as it is for people to guard against typhoon, it is advisable for a man to stop 17 for a moment before he complains. " 18typhoon disappeared all together? What would the world become then?" The 19 will keep him calm and lead him closer to truth-he will be better 20 of the world he lives in. | ||||
|