下列说法不正确的是
A．常温下，氧气与所有金属都能反应
B．棉花属于天然有机高分子材料
C．结晶水合物属于纯净物
D．中和反应一定有盐和水生成
答案：A
A、常温下，氧气不与金等反应，故A说法不正确；
B、棉花属于天然有机高分子材料，故B说法正确；
C、结晶水合物属于纯净物，故C说法正确；
D、中和反应是指酸和碱反应生成盐和水的反应，故D说法正确。
| 完形填空。 | |||
| Do you know who invented tea? In fact, tea, the most popular drink in the world ( after water) , was invented by accident. According to an ancient Chinese legend, the Emperor Shen Nong l tea when he was boiling drinking water over an open fire. Some leaves from a nearby bush fell into the water and remained there for some time. The Emperor noticed that the leaves in the water produced a 2 smell. Later he decided to taste the hot mixture. It was quite delicious. And _3 , one of the world's favorite drinks was invented. China is the home of tea, which has more than 4,000 years history. People throughout(遍及) China drink tea daily. 4 the three major drinks-tea, coffee and cocoa, tea is drunk by the largest number of people in the world. Tea from China, along 5__silk and porcelain(瓷器) , began to be known by the world over a thousand years ago and has been an important Chinese export(出口) 6 . Tea leaves are produced mainly in the area south of the Yangtze River, in the provinces of Zhejiang, Jiangxi and Fujian, because of the mild(温暖的) 7 and rich soil there. Longjing, Wulong, Pu'er and Tieguanyin are all 8 _ kinds of tea. Over the past centuries, Chinese people 9__ their unique (特有的) tea culture, which includes tea planting, tea-leaf picking, tea making and so on. Tea is 10 a popular topic which is often mentioned in dances, songs, poems and novels. | |||
| ( )1. A. invented ( )2. A. pleasant ( )3. A. by the way ( )4. A. In ( )5. A. between ( )6. A. at that time ( )7. A. climate ( )8. A. interesting ( )9. A. had developed ( )10. A. too | B. found out B. pleased B. on the way B. For B. with B. from now on B. weather B. important B. have developed B. as well | C. discovered C. bad C. on its way C. Of C. except C. since then C. condition C. famous C. developed C. either | D. tried out D. terrible D. in this way D. By D. besides D. since now D. environment D. normal D. are developing D. also |