In nature, you may see many insects (昆虫) and animals of different colors. Have you ever wondered why?

Locusts (蝗虫) are super delicious food for birds, but it is not always an easy job for birds to catch them. It is neither because locusts are good jumpers or runners nor because they are smarter than their enemies (敌人). The reason is that the colors of locusts change with the colors of crops (庄稼). When crops are young, locusts look green. But when autumn comes, locusts change to the yellow and brown color as crops do.

Brown bears, tigers and other animals move quietly through forests. They can’t be seen easily by their enemies. This is because they have colors similar to the trees. For the same reason, polar bears that live on a land of snow and ice are white. Butterflies and bees living among the flowers are colorful like flowers. Soil insects are mostly dark-colored and they live under the soil in a dark and wet environment. However, insects with colors different from plants can easily be found and eaten by others. So in order to live,theyhave to hide themselves in the daytime and come out only at night.

Have you ever noticed some even stranger acts (行为) ? The ink fish in the sea can send out some very black ink when it faces danger. As the ink spreads over, its enemies will find themselves suddenly in a dark world. At the same time the inkfish swims away at once. That is how it keeps itself safe though it is not strong at all.

Good study habits are important for all students. When you have good study habits, you’ll learn faster and find you have a good memory.

Do you usually study in the living room? This is not a good place for study because it is usually too noisy. You need to study in a quiet place, such as your bedroom. A quiet place will help you learn better.

Before you begin to study, do not forget to clean your desk. It helps you study well, too. Light is important, too. You’ll feel tired easily if there is not enough light.

Of all the good study habits you can develop, asking questions is the key. Just ask. No one knows everything, but we can always learn from each other by asking questions.

One simple but important habit is to tell yourself what you’re studying for. Putting your dream grade on the wall next to your bed or computer means you’ll see and think about it every day.

When do you work best? Are you an early bird, a night owl (猫头鹰), or something in between? Find your most productive work time, and then plan to study at this time.

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