For centuries, humans have made great efforts to study the Moon. Galileo, the Italian astronomer, noticed the mountains and lands on the Moon with a telescope(望远镜). In 1969, the US Apollo 11 project marked the first time that humans set foot on the satellite. Recently, China' s Chang'e 6 brought back the rocks and soil from the far side of the Moon for the first time in history. You may wonder: what is the value of exploring the Moon?

 Many scientists believe that the Moon was made of the rocks and dust from the baby Earth. When the solar system(系统) just formed. a Mars-sized object crashed into the Earth. The force of the crash was so great that it sent materials from the Earth, and from the object that hit it, back into the space. Some of the rocks and dust stuck together and created the Moon. 

 Those materials on the Moon's surface(表面) have stayed unchanged for over three billion(十亿) years, since it does not have an Earth-like atmosphere. This simple fact makes our Moon a time capsule, which allows scientists to uncover the Earth's past. 

 It is also about our future. In the last two decades, water was discovered on the Moon. It may help future humans look for drinkable water, breathable air, and rocket fuel outside the Earth. Besides, the Moon is a proper place to test technologies required for deep space exploration, including sending humans to Mars. 

 Considering the important role that moon exploration plays in scientific research and human future, scientists suggest that human activity on the Moon should avoid bringing harm to its environment. 

Blue is a very common color in our lives-the sky, the sea and even face masks are often blue. But this color is not frequently(经常) seen in plants. Why is that?

A. Because blue plants would blend in(融合) with the sky and sea. 

B. Because animals prefer to eat blue plants. 

C. Because the material that gives plants a blue color is rare(稀有的)

D. Because blue isn't a beneficial(有助的)color for plant growth. 

The correct answer is D

There is no true blue pigment(色素)in nature. When light hits an object(物体), the object absorbs(吸收)some colors and reflects(反射)others. For example, plants look green because they reflect green light and absorb other colors. Blue light offers more energy than other colors. However, if a plant has blue leaves, according to scientists from the University at Adelaide in Australia, it must absorb(吸收) very small amounts of energy while reflecting high-energy blue light. This is not a good strategy(策略) for growth. 

Less than 10 percent of plants are blue. Plants make blue flowers by mixing pigments. For example, anthocyanins(花青素)can turn into a blue-likes color with a certain amount of acidity(酸度). Plants may make use of this unique color to attract pollinators(传粉者), such as bees. 

If you want to enter the subway, you have to hold your transportation card or smart phone in your hand. Would it be a trouble if you are busy with other things, such as taking care of your children or dogs. 

Now, good news has arrived for some passengers. A subway line in Shenzhen uses 3D facial recognition(人脸识别) technology to help recognize passengers. All they need to do is downloading(下载) the required app, and then they can enter the station just by looking into a screen at the gate for about 2 seconds. In this way, they can enter the subway more quickly than scanning a OR code (扫描二维码). The new technology greatly speeds up entry times. Now, about 30 to 40 passengers can pass through the entrance every minute. 

Facial recognition has been used in many other areas of our life. At KFC stores across China, customers can order their meals by scanning their faces in front of a self- serving screen. Customers used to carry bank cards or mobile phones to withdraw money, but now they can do that just by scanning their faces at the ATMs of banks. With the help of this technology, the security check(安检) step in the airport can be completed in about 12 seconds, according to Guangzhou Baiyun International Airport. 

Do you think facial recognition will totally take the place of OR codes?

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.