We often talk about snails (蜗牛) and their slow move. But usually snails don't move at all. They are in their shells(壳)— sleeping.

Hot sun will dry out a snail's body. So when it is very hot, a snail draws(移动) its body into his shell. A snail will die in a heavy rain. So when it rains, a snail does the same thing, too. A snail can sleep for a long time. It spends all the winter in its shell, sleeping.

In spring, the snail wakes up. Its body is only about 007 meter long out of the shell. When hungry, the snail looks for food. Its eyes are not very good. But it does very well in smell. This helps the snail to find food and the new plants.

A snail's mouth is no bigger than a full stop(句号). But it has 256,000 teeth! The teeth are very small, and you can't see them. And if its teeth are too old, it will grow new ones.

" Am I an'I' person or an 'E' person?" It is a popular topic among young people around China today. Many people are crazy about it so that they take a personality test named MBTI to find out the answer.

Many people find the test useful. It groups people into 16 types, which start with the letter"I"or" E", such as" ENTJ" and"INFP"." E" is short for" Extroversion" while"I" is short for" Introversion". After testing, some say," I'm extroverted; I should go to parties and make friends," while others think," I'm introverted; I prefer working alone, and maybe I' ll be a writer someday." They believe knowing their type can help them make quicker choices about activities, careers, and life paths.

However, there are some problems with the test. Some get different results when they retake it, and some find it hard to answer certain questions. For example," I like watching TV alone, but I also enjoy hanging out with friends. Am I an'I' person or an'E' person?"

When you take a personality test, you may think," Oh, that's me." That's because the descriptions are generic. They can be used to describe many people. Research has found that over50% of people got a different score when they retook the MBTI test just five weeks later. Personalities can change with time, and they are not black- or- white, scientists say. You may be introverted now but become extroverted when you get older. Or, you can be both an"I" person and an"E" person. Don't label(贴标签) yourself! Studies have also shown that the test is not real at telling people's success in different jobs. So, don't take it too seriously.

①Why do we do the things we do? What drives our behavior? Researchers have suggested different ways of thinking about motivation (动机), including looking at whether motivation comes from outside or inside a person.

②Extrinsic(外来的) motivation is when you decide to do something because you want to get a reward or avoid punishment. Intrinsic (内在的) motivation is when you do something because you find it enjoyable. The behavior itself is its own reward.

③There are many advantages of intrinsi c motivation. Firstly, it's lasting. It makes people willing to face challenges and work hard to achieve their goals. Besides, people with intrinsic motivation have a greater sense of satisfaction.

④Most people think intrinsic motivation is best, but it is not always possible in every situation. Sometimes a person has an unpleasant task and he may not have internal(内部的) wish to complete it. That's when we need extrinsic motivation. But studies have shown that offering too many external (外部的) reward can reduce intrinsic motivation. For example, in a study, they became less interested in the toys.

⑤Both extrinsic and intrinsic motivation play a key role in learning. Experts have argued that traditional education pays too much attention to external rewards, such as grades. This undermines the intrinsic motivation that students might already have. However, others have suggested that extrinsic motivation can help students feel more knowledgeable in class. It helps to build up their intrinsic motivation. 

⑥Understanding how each type of motivation works and when it is likely to be useful can help people complete tasks and improve their learning.

Every year, millions of birds are killed or hurt when they fly into buildings. Why does this happen?  Birds are flying into windows and tall buildings that are all covered by glass.

Many birds fly from one place to another. Most of the time, they live in the wild, such as forests and wetlands.  They might see small trees and flowers inside a window and want to rest on these plants. The birds do not know there is glass between them and the plants.  

Some birds fly at night. They use the moon and stars to help guide them in the right direction. Tall buildings with lights on at night can confuse（迷惑）the birds.  The birds see the light, but they cannot tell that the light is coming from inside a building. They fly toward the light and crash into a building. On many mornings, there might be several dead birds lying on the ground.

  Many office buildings now turn off their lights at night. This helps reduce the number of birds that fly into buildings and it also helps save energy.

Most kids love sweets. Why？When we eat or （喝）sweet foods, the sugar enters our blood and influences our brain. It （留下）god feelings with us, making us want more. In fact, all （美味的）foods do this, but sugar has an especially strong power. That's why doctors （总是）advise us to Early humans often had very little food, so our （身体）learned to store a lot of sugar as fat. In this way, we （节省）energy for when there was no food. But today, most people have more than enough. So it may now be harming our （健康）.

It's certain （更少的）sugar. The trouble is that, in today's world, our foods are filled with sugar. Although our （餐）look better, large amounts of sugar are often added. To solve the problem, we should take more exercise, （两次）a week at least. And remember, next time you want some cookies, eat an apple instead.

Brainstorming is the practice of coining up with ideas or solutions. But we do have some rules to follow for successful brainstorming.

Focus on quantity （数量）over quality. When it comes to brainstorming, the more ideas, the better.

Don't worry about the quality of your ideas for now. Remember that your goal is to come up with as many ideas as possible. Even if none of them are perfect, you'll still have many creative ideas to use for your final plan.

Encourage big or unusual ideas. Although unusual ideas may not be immediately practical, just creating those ideas gives your brain training. It can also help to produce creative solutions that are hard to come up with.

Don't say no to the ideas of others. You can put together the best parts of different ideas to create new, even better ones. Even if you're not brainstorming as a group, you should still think about sharing your ideas with others and asking them for their advice.

You don't have to regard yourself as a very creative person to come up with excellent ideas and solutions at once. Even if you don't find the perfect solution, just practicing it can help to improve your creativity. Put these tips together and you are sure to come up with some great ideas.