2017年全国卷2

D

When a leafy plant is under attack, it doesn’t sit quietly. Back in 1983, two scientists, Jack Schultz and Ian Baldwin, reported that young maple trees getting bitten by insects send out a particular smell that neighboring plants can get. These chemicals come from the injured parts of the plant and seem to be an alarm. What the plants pump through the air is a mixture of chemicals known as volatile organic compounds, VOCs for short.

Scientists have found that all kinds of plants give out VOCs when being attacked .It’s a plant’s way of crying out. But is anyone listening? Apparently. Because we can watch the neighbours react.

Some plants pump out smelly chemicals to keep insects away. But others do double duty. They pump out perfumes designed to attract different insects who are natural enemies to the attackers. Once they arrive, the tables are turned. The attacker who was lunching now becomes lunch.

In study after study, it appears that these chemical conversations help the neighbors .The damage is usually more serious on the first plant, but the neighbors, relatively speaking, stay safer because they heard the alarm and knew what to do.

Does this mean that plants talk to each other? Scientists don’t know. Maybe the first plant just made a cry of pain or was sending a message to its own branches, and so, in effect, was talking to itself. perhaps the neighbors just happened to “overhear” the cry. So information was exchanged, but it wasn’t a true, intentional back and forth.

Charles Darwin, over 150 years ago, imagined a world far busier, noisier and more intimate (亲密的)

than the world we can see and hear. Our senses are weak. There’s a whole lot going on.

32. What does a plant do when it is under attack?

A. It makes noises.

B. It gets help from other plants.

C. It stands quietly

D. It sends out certain chemicals.

33. What does the author mean by “the tables are turned” in paragraph 3?

A. The attackers get attacked.

B. The insects gather under the table.

C. The plants get ready to fight back.

D. The perfumes attract natural enemies.

34.Scientists find from their studies that plants can .

A. predict natural disasters

B. protect themselves against insects

C. talk to one another intentionally

D. help their neighbors when necessary

35.what can we infer from the last paragraph?

A. The world is changing faster than ever.

B. People have stronger senses than before

C. The world is more complex than it seems

D. People in Darwin’s time were imaginative.

答案解析：

32. D. 根据第一段的内容，当植物受到攻击时，它会释放出特定的化学物质，这些化学物质来自植物的受伤部分，似乎是一种警报。因此，正确答案是D。

33. A.第三段中提到，一些植物会释放出香味来吸引攻击者的天敌昆虫，一旦这些天敌昆虫到达，攻击者就会变成食物。这里的“the tables are turned”意味着情况发生了逆转，攻击者变成了被攻击的对象。因此，正确答案是A。

34. B. 根据第四段的内容，研究表明这些化学交流帮助了邻近的植物。第一个植物通常受损更严重，但邻近的植物相对安全，因为它们听到了警报并知道该怎么做。这表明植物通过释放化学物质来保护自己免受昆虫的侵害。因此，正确答案是B。

35. C. 最后一段中提到，查尔斯·达尔文在150多年前就想象了一个比我们所能看到和听到的世界更加繁忙、嘈杂和亲密的世界。我们的感官是脆弱的，有很多事情正在发生。这表明作者认为世界比我们看起来要复杂得多。因此，正确答案是C。