For a long time, scientists believed that only humans were left-handed or right-handed.
In Ireland, scientists studied a group of 42 cats. They gave them three tasks.
| A．One of tasks was to get a piece of delicious fish out of a bottle. |
| B．Many people believe that polar bears are left-handed. |
| C．However, recent studies have shown that this isn’t true. |
| D．Scientists are still learning about animals and their behaviors. |
| E．Being left-handed or right-handed isn’t limited (限定) to arms and legs. |
相似题推荐
【推荐1】Are you one of people who are very afraid of something? If you are, you may have a phobia. A phobia is a very strong feeling of being afraid of something. It is often caused by a certain situation or object. In general, there are three kinds of phobias.
To begin with, people with the agoraphobia will be nervous when they stay in a strange place, especially a new place. Then people with the social phobia will feel anxious when they are at a social event, such as speaking in front of many people. Lastly, there is a special phobia. People with this phobia are afraid of special objects or animals, such as spiders and mice.
What should we do if we have a phobia? Many people choose to do nothing, while others try to keep away from what may make them scared. Psychologists, however, say that we need to go to see a doctor. The phobia can get worse easily, and it may affect our sleep and work. Moreover, we can listen to some soft music or do some exercise to relieve it.
1. The underlined word “phobia” means “________” in Chinese.| A．厌食症 | B．恐惧症 | C．狂犬症 | D．妄想症 |
| A．Three. | B．Four. | C．Five. | D．Six. |
| A．social phobia | B．special phobia | C．agoraphobia | D．serious phobia |
| A．ways to treat phobias | B．some great psychologists |
| C．some kinds of phobias | D．the disadvantages of phobias |
| A．If a girl is afraid of snakes, she must have the agoraphobia. |
| B．Listening to the soft music can’t relieve phobias. |
| C．If we have a phobia, we should do nothing. |
| D．The phobia can become worse easily. |
【推荐2】This is a street crossing. There are red and green lights at each corner. Drivers must watch the lights carefully.
When there is a green light, the cars may go on. When there is a red light, the cars must stop. They must wait until the red light changes to green. Then they can go on.
Sometimes the cars want to make a right turn or a left turn. They can make a right turn when the light is green or red. But they must wait until the green light is shining if they want to turn left.
Some people are color-blind(色盲) .They can't see the difference between red and green. These people must not drive, otherwise(否则) there may be an accident. We must keep our street safe.
1. Drivers must pay attention to(注意)_______ at each corner of the street crossing.| A．the red light | B．the green light | C．the red and green lights |
| A．the green light shines | B．the red light shines. | C．there is a light |
| A．a red light | B．a green light or a red one | C．a green light but not a red one |
| A．When | B．if | C．until |
| A．Arrives | B．walks | C．drives |
【推荐3】With their long tusks (象牙), elephants look elegant (优雅的) and strong. However, this unique (独特的) feature is the same reason why the animal is endangered. Many of them are killed for their tusks. People make elephant tusks into crafts (工艺品) and jewelry (珠宝) and sell them to rich people.
But can these prıceless body parts grow back? The answer is no. The tusks are gone forever after being removed, Live Science said.
The elephants’ tusks are actually part of their teeth. Nearly all African elephants and most male Asian elephants have these long teeth. About one-third of the tusk is embedded (嵌入) in the animal’s skull (头骨). The tusk has a nerve (神经) running down its center. This makes it similar to your teeth. Once you lose a tooth, you will never grow a new one.
Elephants use their tusks to protect themselves, lift objects, dig for water and gather food. But losing the tusk is not what kills them. The way in which they lose the tusk is what matters. Usually, people get tusks by culling (限量捕杀), which means killing old and weak elephants. They also take tusks from the elephants that have died naturally.
However, these sources aren’t enough to keep up with the demand (需求) for ivory. Therefore, some poachers (偷猎者) poison healthy elephants and cut their faces open to remove the tusks. About 27,000 elephants are killed by poachers each year, according to National Geographic.
As a result of poachıng, some African elephants gradually evolved (进化) without tusks, which has allowed them to survive (生存). In the country of Mozambique, there was a civil war that lasted from 1975 to 1992. At that time, about 90% of African elephants were killed for their ivory and meat. The ivory was sold to buy weapons (武器) and the soldiers ate the meat, National Geographic reported.
Scientists recently found that about a third of younger females—the generation born after the war ended in 1992—never developed tusks.
1. Elephant tusk are similar to human teeth because ________.| A．they are sharp and long | B．they have nerves inside |
| C．they are connected to the skull | D．they get loose very easily |
| A．The functions of elephant tusks. | B．What it costs to poach elephants. |
| C．How people get elephant tusks. | D．The number of elephants that are killed each year. |
| A．Killing elephants for ivory is legal in African countries. |
| B．Elephants can live a normal life after losing their tusks. |
| C．African elephants were born without tusks after 1992. |
| D．Elephant tusks can’t grow back after being removed. |
