【推荐1】We have always been interested in the moon. 2, 000 years ago, people already knew it moves around the earth and where it would be in the sky at different times of the year. At that time, everything about the moon was learned by watching it carefully in the sky.

When scientists could use telescopes to study the moon more closely, their ideas began to change. They could see the moon was made of rocks. Most scientists thought moon rocks would be different from those on the earth. This was because they believed the moon had once been a planet that had been caught in the earth’s gravity (重力) millions of years earlier.

In 1969, moon rocks were finally brought to the earth and studied. Much to their surprise, scientists found that, except for water, the moon and the earth were made of the same things. Once again new ideas were needed for this new information.

After years of study, most scientists now think that the moon was once part of the earth. They believe very early in its history, maybe 4 billion years ago, something about the size of Mars hit the earth. This sent billions of rocks into space around our planet. These rocks slowly joined together and after many years became the moon.

In the future, though our ideas about the moon may change again, we will still be interested in it.

【推荐3】Do you want to celebrate your birthday in space? It would be very different from what you might do on earth.     1     The candles could not be lit because astronauts cannot start a fire in the spaceship.     2     Voices are almost the only things that are not changed by being weightless, which means that everything has almost no weight in space.

Some astronauts feel sick for the first few days in space. Some feel as if they have a cold all the time. That’s because without gravity, the fluids (液体) in their bodies move towards their heads. Their faces look a little fatter.     3    

And because gravity is not pressing on the spine (脊椎). The spine relaxes and stretches (舒展).     4     But when they come back on earth, they shrink (收缩) to their regular height.

Since nothing has weight, astronauts can lift heavy objects easily.     5     However, it is harder to stay still in space than to move around, so the astronauts always hold onto something or tie themselves to something.

【推荐1】The library is a great place to visit for help with schoolwork. But the library isn’t just about reading and learning. You can have fun in the library, too. Some libraries have fun things for children, like reading tests and making things. And when you go to your library, there is always someone there to help you find what you want. That someone is a librarian.

You can ask your librarian to help you find books about any subject. Libraries have books about everything from planes to animals. If you like to read fictions（小说）, your librarian can help you find them quickly. If you are having a hard time finding an answer to a question, ask your librarian to help you find the answer. Your librarian can help you locate information（信息） in magazines and newspapers, and on the computer.

Libraries are also great places if you want a relaxing place to read or study. They have good chairs, and you can read a book there. They also have tables for you to work on schoolwork. And most libraries have lots of bright reading places, so you won’t hurt（伤害）your eyes by closely looking at that small print.

Don’t forget to visit your library.

Mukbang is about the eating shows in front of the screen. In the shows, mukbangers eat food and sometimes talk to their fans.

Mukbang started in South Korea (韩国) in around 2010 and is becoming well-known in the whole world now. Why did mukbang first appear in this country? The reason is that eating by oneself is quite normal in South Korea. Watching mukbang can be a way to have someone to eat with when they are at home by themselves.

This is one of the reasons why many people around the world like watching mukbang. However, the way mukbangers eat food in some shows isn’t healthy. This can make people have bad habits and bring serious health problems. What’s worse, to have more fans and make more money, some mukbangers prepare a lot of food in front. But they throw away much food during the show or throw up (吐) food after the show to make watchers believe they eat up everything. In fact, it is not because they feel ill. These mukbangers waste (浪费) a lot of food.

We all know that food waste is a serious problem around the world, and stopping food waste has a special meaning for our country. So our country is doing a lot of things to solve the problem. What do you think our country can do for mukbang?

A．	B．
C．	D．

【推荐3】Historically, most cars have run on gasoline（汽油）, but that may change in the future: cars can also run on other liquid fuels（液体燃料）and electricity.

Gasoline is from oil. The energy in gasoline comes from hydrocarbons（碳氢化合物）. Gasoline provides great power for cars. However, it causes environmental problems, like air pollution and temperature rise. So gasoline can’t be the best fuel.

Another choice is electricity. Electricity cars can be as efficient（效能好的）as cars using gasoline. And they produce less pollution. But electric cars themselves are more expensive. Good news is that the cost has been lower and there are more and more places for the cars to get electricity ever since 2010.

The other choices are other liquid fuels. Many of these can be stored in the same places as gasoline, and used in the same cars. They can also be friendly to the environment.

One way to make such fuels is to get CO₂ from the air and put it in water. Through chemical reaction, hydrocarbons can be created. However, these fuels take up more space.

Another way is to make such fuels from plants which take in carbon from the air. These fuels are greener in use. But not all of them can be as efficient as gasoline.

For a fuel to be the best, people have to be able to afford it. Unluckily, almost every green technology is more expensive than that of using gasoline. Governments and car producers are doing everything they can to cut down the costs. In the end, the best fuel will be both affordable for car users and green for our planet.