The apartment has floors and Mr. Smith lives on the floor with his family.A.twelve; twelve B.twelfth; twelfth C.twelve; twelfth D.twelfth; twelve 题目和参考答案——青夏教育精英家教网—

题目内容

The apartment has _________ floors and Mr. Smith lives on the _________ floor with his family.

A.twelve; twelve B.twelfth; twelfth C.twelve; twelfth D.twelfth; twelve

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Daming: Have you ever read the novel War and Peace?

Betty:1.

Daiming: What a pity! It’s a wonderful book.

Betty: Well, I've been waiting to read it for a long time, but I can't get a copy. The library has only three copies. 2.

Daming: Well, 3.If you like, I'll lend it to you.

Betty: Thank you.4.By the way, when can I get it?

Daming:5.Will you please come to my house after school?

Betty: OK. I’ll go as soon as school is over.

A.That's very kind of you.

B.I forgot where I had put it.

C.You really should read it.

D.But they are all out.

E.I’m afraid I haven't.

F.I haven't had it with me.

G.I have a copy of my own!

Beyond ________stars, the astronaut saw nothing but _______space.

A./; the B.the; / C./; a D.the; the

— I don’t know tomorrow.

— You can ask our teacher right now.

A.if we take the bus there B.when will we leave

C.what will we do D.how we will go there

—Why didn’t you come to my birthday party, Sally?

—Sorry, I was so busy that I _______ forgot it.

A.luckily B.completely C.hardly D.clearly

Could you please put some _________ in my cup? I’d like sweet coffee.

A.sugar B.salt C.ice D.pepper

There will be heavy rain and strong wind next ___________ / wi:k /.

A.week B.wait C.west D.weak

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

We spend hours, days and years of our lives in school. Imagine you could design（设计）your dream school, what would it be like? What would you be doing? We wanted to find out what teenagers around the world thought.

Here is what they said:

Richard from the USA: My dream school would have a big swimming pool. It would also have a cinema, a gym and a shopping center. My school has none of these and I think there should be more pleasant things for students to do while they are studying.

Sonia from Italy: I’d like a room where we can relax and play computer games. I’d also like to have a music room. I think there should be a place for everyone to go and relax after class.

Wu from Beijing: I think it would be great to have another day off every week, besides the weekend. If that day was a Friday or a Monday, we would have a long weekend every week. What fun! I also think school should start later, at about 10 o’clock, and finish earlier.

Hannah from Australia: In my dream school, I think the teachers should give us more freedom and choice about how we study and what we study. I also think it’s not necessary for us to wear school uniforms every day. I really don’t like wearing it.

根据材料内容，选择最佳答案。

1.There would be __________ in Richard’s dream school.

A.a big swimming poor and a music room

B.a room to relax and play computer games

C.a long weekend, three days off every week

D.a big swimming pool, a cinema, a gym and a shopping center.

2.Wu wants to have ____________ days off in a week.

A.2 B.3 C.4 D.1

3.The country of ___________ is NOT mentioned in the passage.

A.Italy B.Australia C.Japan D.USA

4.In ___________ dream school, the teachers should give them more freedom and choice for study.

A.Richard’s B.Sonia’s C.Wu’s D.Hannah’s

5.From the passage, we know that __________

A.Sonia from Italy would like a room where she can relax and play computer games

B.Richard from the USA think his dream school should start at 10 o’clock

C.Wu from Beijing thinks it would be great to have two days off every week

D.Hannah from Australia likes wearing a school uniform every day

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