Smart phones play an important role now. As l...

Smart phones play an important role now. As long as we take them，we can ______ many problems easily.

A.deal with B.stick to C.cut off

九年级英语单选题中等难度题查看答案及解析

—Great changes have taken place since we ________ E-times. And smart phones play an important role in our life, especially Iphone 6s came out recently.

—So it is. Our future life will be colorful .

A．entered

B．will enter

C．have entered

九年级英语单项填空中等难度题查看答案及解析

Xiongan New Area __________ being built as a green and smart city，and it plays an important role in China's development.

A.is known for B.is worried about C.is born with

九年级英语单选题中等难度题查看答案及解析

Everyone can play an important role in the society. As members, we should try our best to do________.

A.what we should do B.what shuuld we do

C.how we should do D.how we should do

九年级英语单选题中等难度题查看答案及解析

As a student, books play an important role in our life. As Gorky once said, “Books are the ladder of human progress.” Then which book is your favorite?

As a book lover, my favorite book is Robinson Crusoe. This book is 1.（写）by Daniel Defoe, and it has already 2.（影响）lots of students like me. Every time I read it, I see a tall and strong image of Robinson. The 3.（整个的）book tells the stories of his adventures and courage. He is such a brave man that I4.(钦佩) him so much. When Robinson was young, he dreamt of sailing on the sea day and night. Unfortunately, after his grown up, he 5.（实际上）lived on a desert island for twenty-eight years. He6.（经受）a lot. But the idea of 7. up（放弃）never came to his mind. During these years, he had to endure hunger, fight against 8.（自然的）disasters, and overcome many 9.（困难）. But the great man went out of the desert island at last because of his fighting 10.（精神）, and hard-working attitude. That story encouraged me deeply. Our life cannot be lucky all the time. But no pains no gains. And only hard work can lead us to a better life.

九年级英语单词填空困难题查看答案及解析

Bacterial Quorum Sensing

Bacteria(细菌)play an important role in our lives. They can keep us alive as well as make us sick. It wasn’t until fairly recently that we learned bacteria can communicate with one another.

In the 1960s, researchers found that a kind of bacteria called Vibrio fischeri（费氏弧菌） produced no light when they were alone, but that they exhibited great amount of light as the bacterial population grew to a certain number. How did this happen? How can Vibrio fischeri tell the difference between times when they’re alone and times when they’re in a community, and then all do something together?

Researchers found they talk to each other with a chemical language—signal molecules(信号分子). Vibrio fischeri makes signal molecules, and it also has a receptor on its surface that fits like a lock and key with a signal molecule. As the bacteria increase, more and more signal molecules are sent into the environment. When signal molecules increase to a certain amount, they lock down into those receptors and information comes into the bacteria, which tells them how many neighbors there are. As soon as they realize the population has hit the certain number, all of the bacteria behave as a group, making light together. In the past ten years, researchers have found all bacteria have systems like this: they make and recognize chemical words, determine(判断)the size of the community, and carry out tasks that would be unsuccessful if a single one were to act alone. This process is called quorum sensing.

Most of the time, bacteria live with thousands of other species (种类)of bacteria. There has to be a language of interspecies communication. In fact, bacteria have another kind of signal molecule, which is the common language used by all species. Moreover, this kind of molecule has its own receptor. In this way, bacteria are able to count different populations, and then they decide what task to carry out depending on which species has the greatest population.

Knowing how bacteria communicate could influence how we fight disease. What if bacteria can’t talk or hear? They won’t recognize when there are enough bacteria and when to exhibit the group behavior to make us sick. Researchers are developing a method—to make molecules that look like the real ones and then they lock into the receptors to jam recognition of the real situation.

On the other hand, researchers also improve the conversation of the beneficial bacteria, so they can do things that we want them to do better than they would do on their own.

1.According to the passage, what can we learn about quorum sensing?

A.Quorum sensing may happen when there is only one Vibrio fischeri.

B.Signal molecules are kept away from receptors during quorum sensing.

C.Most bacteria have similar systems to make light during quorum sensing.

D.Bacteria carry out a group task when their population hit a certain number.

2.What can we learn from the passage?

A.The more species there are, the more group actions bacteria will take.

B.In different environments, bacteria have different interspecies languages.

C.Beneficial bacteria communicate better by themselves than harmful ones.

D.To fight disease, researchers try to turn off the communication between harmful bacteria.

3.The passage is mainly about ________.

A.why bacterial population grows B.how bacteria communicate with each other

C.which bacteria help fight disease D.what scientists do to find quorum sensing

九年级英语阅读单选中等难度题查看答案及解析

More and more people are using mobile phones now. Smart phones are used as televisions, cameras, and music players. They are also used for sending e-mails or surfing the Internet. If someone talks about mobile phones, many Chinese will think of Huawei.

In China, even in the world, Huawei is a wonder in 2019. Ren Zhengfei set up Huawei company in 1987. The company sold about 58.4 million smart phones in the first season of 2019. Huawei has got the second place at the mobile market.

Now, Huawei has been the leader in the 5G field. It has more than 75,000 top engineers and scientists on research. They try their best to bring digital and high technology to every person and place. It's more convenient for modern people to live in a rapid way. What a useful technology 5G is!

We are looking forward to seeing a stronger Huawei. It provides a faster and better communication way for us. It also brings “Created in China” to the world.

根据短文内容，判断句子正(T)误(F)。

1.More and more people use mobile phones to surf the Internet .

2.The man named Ren Zhengfei build up Huawei company in 2019.

3.Smart mobile phones has got the second place at the market in the world.

4.Over 7,500 engineers and scientists make efforts on research in Huawei company.

5.Huawei offers a quicker communication way to the world.

九年级英语阅读判断困难题查看答案及解析

Everyone can play an important part in society. As members, we should try our best to do __　　　 .

A. how we should do　　　　　　　　　　　　　　 B. what should we do

C what we should do　　　　　　　　　　　　　　　　 D. how should we do

九年级英语单项填空困难题查看答案及解析

Everyone plays an important part in society.　 As members, we should try our best to do

　　　　 to make the world better and better.

A. what we should do

B. what should we do

C. how we should do

九年级英语单选题困难题查看答案及解析

根据短文内容及首字母提示，填写所缺单词。

More and more people are using mobile phones now. Smart phones are used as televisions, cameras, and m1. players. They are also used for s2. emails or surfing the Internet. If someone talks about mobile phones, many Chinese people will think of Huawei. In China, even in the world, Huawei is a w3.. Ren Zhengfei built Huawei company in 1987. The company sold about 58,4 m4. smart phones in the first season of 2019. Huawei has got the s5. place at the mobile market.

Now, Huawei has been the l6. in the field of 5G. It has more than 75,000 top engineers and scientists on r7.. They try their best to bring digital and h8. technology to every person and place. It’s more convenient for m9.. People to live in a rapid way. What a useful technology 6G is!

We are looking forward to seeing a stronger Huawei. It provides a faster and better communication way for us. It also brings “C10. in China” to the world.

九年级英语语法填空困难题查看答案及解析