11．　　The invention of barcodes comes from a very simple idea. We only need to give each product (产品) a specific (特定的) number and print it. Then computers can read it quickly. We could just print the number itself. But this can lead to problems. For example, an unclearly printed "seven" could look like a "one" to a computer. It's also true for "three" and"eight". And"nine" looks quite like"six"if you turn it upside down. We need a better way of printing numbers so that they can be read correctly at high speeds. That's the problem barcodes solve.
　　Each number in a barcode is shown by seven blocks (块) of the same size. These are colored black or white to show the number zero to nine. For example, the number "one" is shown in turn by two white stripes (条), two black stripes, two white stripes, and one black stripe. Even if you turn it upside down, it isn't like to any other number.
　　A barcode includes different parts and each one provides a specific meaning, The first part of a barcode tells you the county where the product was made. For example, 690 — 692 is the barcode for China. The next part tells you who produced the product. The final part is about the product itself. This is how barcodes work.

12．Lisa: So you went shopping to! What did you buy?
Wison: Well, I did more looking than shopping! Everything was more expensive than I thought. I bought this toy animals for my little brother. It was 350 yuan.
Lisa: You're lucky, Wilson. I saw the same toy animals in a shop window, and the price was even higher than that. It was 410 yuan.
Wilson: Really? Anyway, what did you find, Lisa?I hope you were luckier than me.
Lisa: Well, I bought a puzzle (智力游戏) book. It had the most unusual puzzles in the shop. But it was cheaper than all the other puzzle books.
Wilson: That's good.
Lisa: I also bought a computer game for myself. It is the most popular computer game at the moment, because it is more interesting than many other games!
Wilson: Great!But computer games are more expensive than before. Did you buy anything else?
Lisa: Yes, I spent my last 10 yuan on the best sweets in the shop.
Wilson: Well, we were luckier than I thought. We bought good things at the lowest prices!

18．　　An encyclopaedia is a collection of information about things humans know. Some encyclopaedias give information on only one subject. Some encyclopaedias give information on all kinds of subjects. Here is a page from an encyclopaedia.

19．　　It is an ordinary ability for humans to tell (分辨) more from less. Surprisingly, a number of animals have this ability too. They will pick more of something. (1)      (horse), for example, will go for a group of three apples instead of two apples.
　　This ability is (2)       (use) to animals in lots of ways. It helps (3)      (they) find the larger group of friends. Many fishes, for example, join groups for safety. If a predator (掠食动物) comes, a fish in a group of 10. So if a fish (4)      (have) a choice between two groups, it's safer to join the larger one. This ability even helps (5)      (keep) safe. For example, a monkey group will stop (6)       (fight) with other groups when they find their number is not an advantage (优势).
　　Also, the ability to count is a sure thing for some animals. They know the difference between one, two, and (7)      (third).
　　Some others can count much (8)      (high) than four.

20．Some computers
　　Smaller and better
　　In the 1940s，the first computers were bigger than cars.Now computers are becoming smaller and better. Some computers are (A) tiny. You may be unaware of them. There is probably one inside your TV or washing machine. You depend on computers more (B)______you realize. Computer facts
　　Smaller and better
　　In the 1940s, the first computers were bigger than cars. Now computers are becoming smaller and better.
　　What can we do with computers?
　　We can use computers to calculate. They can calculate at a faster speed than we can and almost never give wrong answers. (C)We can also type and draw things with them. In addition, computers can do important jobs like operating railways and flying planes and spaceships.
　　Is a computer cleverer than me?
　　The answer is"No". Your brain can (D) produce new ideas but computers cannot. (E)______, one day computers may be able to do a better job than human beings. For example, they may be better than doctors at doing their job.
　　(F)我们将会发生什么. if computers can do all our jobs?Will we have nothing to do?Computers may change our lives, but will they make them better?

21．　　Do you know how rice first came to China? There is (A)______ old Chinese story.
　　It is about a little girl who went out to fish. There was a famine (饥荒) and everybody was very hungry. ①
　　The little girl felt her net (网) growing heavy and was very happy. In fact, what she caught was the King of Frogs (青蛙). (B) When the fog knew the girl would like something to eat.the frog promised that he could help her. The frog told her to hold out her fishing
　　②She Was net to the sun and he would sing a magic song. The little girl did as he told. greatly surprised to see that the sunshine was filling through the net. And it turned into golden grains of rice. The first rice was thought to arrive (C)______this way.
　　Is this story true?We don't know. But it tells us that (D)大米和黄金一样重要to the Chinese.
　　Rice is always the main food for the Chinese. For centuries, much land has been used for rice-planting and may Chinese people are farmers. ③

22．阅读短文, 然后选出可以填入文中空白处的短语．

　　In 1945, at the end of the Second World War, Percy LeBaron Spencer, an American inventor, was (1)      to produce powerful radio waves. When he was standing (2)      the new machine, the bar of chocolate in his pocket became soft. The machine was able to (3)      ! Percy called it a microwave, and soon many homes began to use it.
　　The first microwave, however, weighed around 350 kilograms and was as big as a fridge!In time, microwaves became smaller and smaller. Now (4)       homes have microwaves and many people can't imagine living without one. Like (5)       that were created by accident, the microwave has changed the way we live.

23．假定你是李华, 参加学校组织的英语征文比赛, 请以"My great invention"为标题写一篇短文．内容包括:
1. 发明物介绍;
2. 发明物特点(外表、优势、工作原理);
3. 发明物评价．
注意:
1. 词数 80 — 100．开头已为你写好, 不计入总词数;
2. 短文须包括所给内容信息．可以适当增加细节, 以使行文连贯．
My great invention
　　My great invention is ______________________________________________________________________________________________________________________________________________________________________________________________________________________