【推荐1】People keep flat-faced (扁脸的) dogs such as French bulldogs (法国斗牛犬) as pets because they are cute. Some people call these dogs “lazy” because they sleep more easily than other dogs during the day. However, these cute dogs are having a hard time.

Scientists in Hungary watched 92 family dogs of different types while they were sleeping. During the study, the dogs spent about three hours with their owners in the sleep lab. When the dogs fell asleep, scientists recorded the dogs’ brain activities.

The study found that the flat-faced dogs slept more than the other kinds. Maybe they don’t get enough sleep at night because of sleep apnea, which only happens in French bulldogs. During their sleep, they can’t get enough air and may find it difficult to breathe, which makes them often wake up.

Some French bulldogs may sleep while holding a toy ball in their mouths. Owners may think this is funny. But they’re doing it to keep their airways (呼吸道) open so they can breathe more easily.

French bulldogs have this health problem because of breeding (培育). According to Pet Helpful, a lot of pet dogs are bred based on what people like, such as shorter legs, heavier bodies, and larger ears. Bulldogs are one of the victims (受害者).

Lots of pet lovers are calling for people to respect dogs as they are. Breeders must take the health of dogs seriously instead of just for cuteness.

【推荐2】Is there life on Mars (火星)? We don’t know. We are sure that people can not live on Mars. People can’t live without oxygen(氧气). There is little oxygen on Mars. Living on Mars would be like living on a very high mountain. There would be little air. It may be 50℃ at noon and -100℃ at night.

Many people think there may be plants on Mars. We know that Mars has carbon (二氧化碳). This is kind of material (物质) and we found it in all plants and animals on the earth. Mars looks red. In some places, it seems gray. Sometimes the gray color turns gray-green then brown, and then gray again. The gray-green color may be a kind of plant life changing color with seasons.

Will man go to Mars one day? If they do, they will have to take their own oxygen, food, clothing and shelter (住所) with them.

【推荐3】Trees do much for human beings, plants and animals. They provide a lot of wood for buildings and things for making paper. They provide homes for all kinds of insects, birds and other animals. They also keep the air clean. Trees are so important to us. But do you know how a tree grows up?

Just like us, trees change a lot as they grow. Between 1 and 3 years old, ▲ . For example, many trees grow thorns(刺) to keep the animals away.

At the age of 15, trees become young adults. They begin to produce flowers and fruit.

It is not until the tree is 20 to 25 years old that it becomes a real adult. The tree reaches its largest size. The adult tree not only gives us shade, oxygen and natural beauty, but also provides a great place for us to rest, read books or listen to music. After that, trees begin to grow older and older and even die. At this time, they still have their important place in nature. When part of a tree becomes dead, it provides a home for small animals.

In many ways, the life of a tree is just like everyone’s own life. Each period of life brings its own joy and challenge. Let’s enjoy every minute of the life of the trees and take care of them.

【推荐1】

【推荐3】Do you have enough sleep? With so much homework to do, it’s often difficult to get the rest you need. But you need to try, because sleep keeps you healthy and it stops you getting fat. Recently, a group of US scientists did a study among some kids between 8 and 13 years old.

The study found that if kids sleep for just one more hour each day, the chance of their getting fat is cut by about 30 percent.

Why? When people don’t get enough sleep, they become tired. When they are tired, they don’t exercise enough. Also, kids like snacks. If they are awake one or two more hours each day, they have more time to eat snacks or other unhealthy foods.

So, how much sleep should kids get? Scientists say it is better to sleep 10 to 11 hours a night for kids 5 to 12 years old. For older kids, eight to nine hours will work.

【推荐1】Try to think about this: you sit down and begin to eat a tomato. Just then, the tomato starts to shout! This may not sound real, but a new study showed that plants made sounds(声音) when they “felt” worried.

Scientists used ultrasonic microphones (超声波克风) to “hear” the sounds of tomato plants in boxes.

What did they do?

They listened to three groups of plants.

Group 1 and Group 2 made sounds 30 to 50 times(次数) every hour. Group 3 only made 1 sound every hour. “When tomatoes are not worried at all, they are very quiet,” Lilach Hadany from the study team said.

Who listens to these sounds?

Animals may listen to the sounds in the forest. For example, the sound can tell them that the plant is worried and not good for laying eggs(产卵) on. When an animal wants to eat a plant, it can also use the sound to pick which one to eat.

The scientists also listened to other plants, like rice. They also made more sounds when they were worried. Scientists say the study can help farmers in the future. They can help the plants grow better by “hearing” how plants feel.