问题 选择题

下列说法中正确的是(  )

A.零下18℃的液体不能发生汽化现象

B.“千里冰封,万里雪飘”这种景象中的“冰”“雪”的形成过程是要吸热

C.烧水时常看到“白气”,从水到“白气”的物态变化是先汽化后液化

D.寒冷的冬夜,家里窗户玻璃上的“冰花”,是由于室外空气中的水蒸气凝华形成的

答案

答案:C

题目分析:液体直接变成气体的现象是汽化现象,零下18℃的液体也可以发生汽化现象;“千里冰封,万里雪飘”这种景象中的“冰”的形成过程是凝固现象,要放热,“雪”的形成过程是凝华现象,要放热;烧水时常看到“白气”,水汽化后变成温度高的水蒸气,这些水蒸气遇冷后又液化成“白气”,所以从水到“白气”的物态变化是先汽化后液化;寒冷的冬夜,家里窗户玻璃上的“冰花”,是由于室内空气中的水蒸气凝华形成的.

A零下18℃的液体不能发生汽化现象,不合题意;B.“千里冰封,万里雪飘”这种景象中的“冰”“雪”的形成过程是要吸热,不合题意;C.烧水时常看到“白气”,从水到“白气”的物态变化是先汽化后液化,符合题意;D.寒冷的冬夜,家里窗户玻璃上的“冰花”,是由于室外空气中的水蒸气凝华形成的,不合题意;故选C.

阅读理解

Did you ever wonder how some of your favorite foods, products or toys came about? Believe it or not, they may have been an accident, or a failure of some other intention. Below, we found three mistakes we’re thankful for turned out to be what they are.

1. Most historians hold that the Chinese invented fireworks in the 9th century when they

discovered how to make gunpowder. Story has it that a Chinese cook accidentally mixed together what were then considered common kitchen items and noticed they burnt. When put tightly in a bamboo tube and lit, it blew up.

2. In May of 1886, a law led John Pemberton, a pharmacist(药剂师), to rewrite the formula(配方) for "Pemberton’s French Wine Coca,” his popular headache treatment. Containing sugar instead of wine as a sweetener, the outcome became something for Coke, which was later mixed with carbonated water. His bookkeeper suggested the name Coca-Cola because he thought the two C’s would look good together, which is how what we call Coca-Cola, a world –wide drink came into being.

3. During World War II, scientists at the University of Birmingham invented the magnetron—an important heat-producing part of the microwave oven(微波炉). While working for Raytheon Corporation after the war, the American engineer Percy Spencer was testing the magnetron when a chocolate bar in his pocket melted. He went on to test other foods including popcorn kernels, and found it to be a much more efficient way to cook. In 1947 Raytheon came out with the first restaurant microwave oven, which was six feet tall and weighed 750 lbs.   

小题1:The right time order of the three inventions, according to the passage, should be_________.

A.fireworks, the microwave and Coca-Cola

B.fireworks ,Coca-Cola and the microwave

C.Coca-Cola , fireworks and the microwave

D.the microwave, Coca-Cola and fireworks小题2:Percy Spencer found the microwave efficient in cooking when he was _______.

A.looking for a way to melt his chocolate

B.trying to know how a magnetron could cook

C.working to know how the magnetron works

D.asked to invent a restaurant microwave oven小题3:What can we learn from the above invention stories? 

A.Experiments make great inventors of our time.

B.Nothing is impossible if one tries each day.

C.Inventors come out of hard work at any time.

D.A small incident may lead to a great invention.小题4:What’s the best title for the passage?

A.What great inventions they are!

B.Inventions from Three Countries.

C.Stories of Accidental Inventions.

D.The Human Inventions of time.

单项选择题 A1/A2型题