Many people say dolphins are intelligent. They can learn, think, and understand things quickly. Scientists say sometimes dolphins show they are really smart, just like humans (人类). How?

Talk

Like humans, every dolphin has its “name”. The name is a special whistle (口哨). Every dolphin chooses a whistle as (作为) its name, usually by its first birthday. Dolphins like to “talk” to each other about a lot of things-such as their age, their feelings, and danger around. Understanding dolphin’s talk is not easy for humans. No one can "speak dolphin"yet, but some scientists are trying to learn.

Play

Dolphins live in groups and they often join other dolphins from different groups to play games and have fun-just like people. Sometimes they run after other dolphins carrying things and throw these things back and forth. Scientists believe playing together is something only intelligent animals do.

Teamwork

Dolphins and humans are similar (相似的) in another way: They both make plans for getting things they want. In the seas of southern Brazil, for example, dolphins use an intelligent way to get food. When there are fish near a boat, dolphins will signal (示意) to fishermen. With the dolphins’ help, fishermen can catch a lot of fish. In return (回报), dolphins can get some to eat.

①Every time you feel uncomfortable, you can check yourself by taking your temperature. So, what’s the average (平均的) human body temperature? Well, if you say 37℃, maybe you are wrong. It turns out that the average body temperature has dropped in the past one hundred and fifty years, according to a new study.

②“Everybody knows that our normal temperature is 37℃, but it is wrong,” said Julie Parsonnet, a Stanford University medical professor.

She and her team looked at medical data (数据) from three different time periods: 1862 to 1930, 1971 to 1975, and 2007 to 2017. Comparing the data, they found that body temperature has dropped by about 0. 02℃ every ten years. So what’s the new body temperature? It’s 36. 6℃, says the study.

③As for the reason, one possibility is that living in temperature-controlled buildings has changed our bodies. They don’t need to work hard to keep the temperature normal. Another is less inflammation (炎症) in people’s bodies. Inflammation makes your body use more energy, which increases body temperature. Progress in medical treatments (治疗) and improved standards of living have led to less inflammation in people’s bodies compared to 200 years ago. No matter what the reason is, our bodies are changing.

④Another interesting fact is that men and women have different ideas about what the comfortable temperature is. According to one study, women are comfortable at a temperature of 24—25℃, which is 2. 5℃ higher than the temperature preferred by men. What’s more, studies have shown that as the temperature drops, women’s blood runs slower than men’s.

⑤ The human body may have changed over the past hundred years, but one thing that has not changed is that men and women have different feeling about what temperature is comfortable.

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Just think for a minute what it would be like if you couldn’t hear. You couldn’t listen to music, hear a dog bark, hear the phone ring or hear your friends talk to you. The world would be a completely silent place to you.

We must know there are three parts of the ear: the outer ear, the middle ear and the inner ear. How do your ears work? The outer ear is what you can see, including the ear canal (道) which collects the sound waves and sends them to your eardrum. The middle ear is a small space filled with air on the inside of your eardrum. In this part of the ear there are three very small bones (骨头). These bones are used to move the sound waves and vibrations (震动) to the cochlea (耳蜗) which is a piece of the ear.

The inner ear has fluid (液体) in it which moves because of the vibrations and moves of small hairs on the outside of the cochlea. There are about 17,000 tiny hairs in each ear. These hair cells create an electrical signal (信号) which is sent to the brain. The brain then works out what you are hearing.

▲ First, try to stay away from the noise. Hearing the noise for a long time will lead to hearing loss. Second, we should keep the ears dry in our daily life. Last, the ears may be influenced by disease and damage (损伤). Diseases of the ears may lead to hearing loss and other problems. So we must look after them well.