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1、1.西城CBacteria(细菌)play an important role in our lives. They can keep us alive as well as make us sick. It wasnt 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 t
2、hey 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 theyre alone and times when theyre in a community, and then all do something together?Researchers fo
3、und they talk to each other with a chemical languagesignal 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.
4、 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 toge
5、ther. 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
6、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, b
7、acteria 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 cant talk or hear? They wont recognize when there are enough bac
8、teria and when to exhibit the group behaviorto make us sick. Researchers are developing a methodto 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
9、 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 sensi
10、ng.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, bact
11、eria 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 growsB. how bacteria communicate
12、 with each otherC. which bacteria help fight diseaseD. what scientists do to find quorum sensingDEverybody hates that feeling when you spend three weeks reading a book, and a month later somebody asks you about it and you cant remember a thing you read. It makes you wonder why you wasted a couple of
13、 hours on the words that didnt stick.There are some effective ways to learn. And when I say “to learn effectively”, what I mean is to not just build up knowledge, but to be able to apply(应用)that knowledge effectively at some point in the future. By this definition, most of the courses people spend m
14、oney on is not learning. Something is not truly learned until it changes you in some way.1. Memory is based on relevance (相关性)One of my favorite online book clubs is Mentor Box. Whats cool about the club is not only do they send you books to read, but they send you study materials related to them. T
15、he study materials, instead of being like school, where it asks you to repeat information in the book to help memorize it, are designed to help you apply the lessons to various areas of your life.Thats because memory works based on relevance. We only remember what our brain has considered important
16、to our own lives. If you dont find a way to make it relevant to you and your well-being in some way, your brain will conveniently forget it.You can do this on your own. When you come across something interesting in a book, write down its application or relevance to something in your lifehow you can use the idea, how it explains something in your past, how it can help with your problems, etc.2. Reading does not have to
