When people talk about the human body, they usually talk about arms or legs, hands or feet, the heart or the brain. Those parts of the body are important, but we often forget about our skin (皮肤) and it is very important, too.

It tells us about the outside, world—whether it is hot or cold, wet or dry. It also tells us if the body is hurt—that is when we feel pain. Skin covers our bodies. Every time we move, our skin moves, too. Try this: pull up the skin from the back of your hand and then let it go. What happens? The skin goes back to its first position (位置) . That means that skin is elastic. We can move it and pull it but it always goes back.

Our skin seems to be very thin but it is made of two layers (层) . The top layer is the one we wash every day. Do you know that this part of the body is dead? However, it is important because it is used for protecting us against dirt (灰尘) and disease. Living skin cells (细胞) travel from the bottom (底部的) layer to the outside of the body. This takes about 27 days.

Skin has millions of very small holes, called pores (毛孔) . Water cannot get into our bodies through these pores but it can get out. Pores allow water from the blood to leave the body—this water is called sweat (汗) . Sweat helps to keep our bodies at the same temperature. When it is very hot, we sweat a lot, but even when it is quite cool, we sweat, too. On a cool day, when it is not hot or wet, our bodies produce about 700 ml of sweat. That is more than 0.5 kilo!

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Do you use WeChat or QQ to chat with your friend? If yes, then you must be a user of memes (表情包), too. Memes are now an important part of online chatting (网上聊天).

Memes can be pictures of GIFs. They are usually of stars, TV and film scenes (场景) or animated Images (动画形象). There is often a line of text (一句话) in a meme. It explains the picture.

The memes of singer Huang Zitao are very popular. Huang runs and says his famous line, “I will not easily go die.” There are some other popular memes, too. TV hostess Dee Hsu rolls her eyes (翻白眼). Basketball player Yao Ming laughs but looks like he’s crying.

These people have exaggerated facial expressions (夸张的面部表情). So users make memes for fun. On the other hand, memes can give people information in an easy, funny way.

If you are quite using the popular memes, then make your own. Memes apps can help you do that. Why not try it for yourself?

Now many people are talking about and using the Internet. But not all of us know the history of the Internet. In fact, scientists began to study the Internet in the 1960s. However, it didn’t work well enough. For example, if one computer in the network (网络) broke down, then the whole network stopped. Scientists kept trying. They set up (建立) a new network system (系统). Many different computers could use it. Even (即使) a computer didn’t work, the whole system would be OK.

At first only government (政府) used the Internet. But in the early 1970s, universities (大学), hospitals and banks (银行) began to use it, too. But it was still very expensive and difficult to use. Then in the 1990s, computers became cheaper and easier to use because of scientists’ hard work.

Now the Internet comes into every part of our life. It’s hard to believe what our life will be like without the Internet.