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Outline：Your essay should be based on the information given below． ①乘飞机旅行有许多长处(方便、快捷、省时、舒适等)。 ②空中旅行也有许多不足之处(机票价格贵，有的旅客不适应空中旅行，常常感到身体不适，甚至有人还担心发生空难)。请你简单阐述上述两个方面。 ③最后请你说明你的看法。
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Poor as he was, he cared little about money reward.
Yesterday they received a written (invite) _________ to a dinner from Mr.Black.
Black holes. They act like huge drains in the universe. Frightening Fascinating Or just fantasy The very concept of black holes confuses our common sense notions of matter, time, and space. The theory that black holes can, and probably do, exist in space doesn’ t only concern scientists and astronomers.(61)For if the theory is valid, we must question all our basic physical laws and, indeed, our "normal" experience of the physical world around us.What is a black hole Well, it’s difficult to answer this question, since the terms we would normally use to describe a scientific phenomenon are inadequate here. (62)Astronomers and scientists think that a black hole is a region of space (not a thing) into which matter has fallen and from which nothing can escape--not even light. So we can’ t see a black hole. A black hole exerts a strong gravitational pull and yet it has no matter. It is only space---or so we think. How can this happenThe theory is that some stars explode when their density increases to a particular point; they "collapse" and sometimes a supernova occurs. The collapse of a star may produce a "White Dwarf" or a "neutron star’--a star whose matter is so dense that it continually shrinks by the force of its own gravity. But if the star is very large (much bigger than our sun) this process of shrinking may be so intense that a black hole results. (63)Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole. Any matter near the black hole is sucked in. It is impossible to say what happens inside a black hole.Our space and time laws don’ t seem to apply to objects in the area of a black hole. Einstein’ s relativity theory is the only one that can explain such phenomena. Einstein claimed that matter and energy are interchangeable, so that there is no "absolute" time and space. There are no constants at all, and measurements of time and space depend on the position of the observer --they are relative. (64)We do not yet fully understand the implications of relativity theory; but it is interesting that Einstein’ s theory provided a basis for their existence. It is only recently that astronomers have begun specific research into black holes.The most convincing evidence of black holes comes from research into binary star systems. In some binary systems, astronomers have shown that there is an invisible companion star, a "partner" to the one which we can see in the sky. There is one star, called by its catalogue number HDE 226868,which must have a partner. This partner star, it seems, has a mass ten or twenty times greater than the sun--yet we can’t see it. Matter from HDE 226868 is being dragged towards this companion star. Could this invisible star, which exerts such a great force, be a black hole Astronomers have evidence of a few other stars too, which might have black holes as companions.The story of black holes is just beginning. Speculations about them are endless. There might be a massive black hole at the center of our galaxy swallowing up stars at a very rapid rate. Mankind may one day meet this fate. On the other hand, scientists have suggested that very advanced technology could one day harness the energy of black holes for man’ s use on earth. There are also suggestions that black holes could be used to create bombs in the future, by amplifying radio waves sent up to them. These speculations sound like science fiction. But the theory of black holes in space is accepted by many serious scientists and astronomers. (65)They show us a world that operates in a totally different way from our own and they question our most basic experience of space and time. They show us a world that operates in a totally different way from our own and they question our most basic experience of space and time.
W: It’s well-known science fiction plot to freeze a body and bring it back to life years later.However, this may no longer be so far from the truth. Joining us from our Cardiff studio is Professor Andrew Morgan, who’s been doing some research into this subject. Professor Morgan.M: Yes, well, I’ve been looking into the ability of certain animals to freeze themselves for a certain amount of time, and then to come back to life when the circumstances around them change. And, what I’ve been working on over the past two years is the particular process that enables them to do this.W: What have you actually discoveredM: I think it’s a particular chemical in the animals’ bodies which begins to work under certain circumstances. And I’m now experimenting with this chemical to see if I can get other animals that wouldn’t normally be able to freeze themselves to be able to do this.W: Have you had any successM: I have so far. It’s been going very well. And I’m reasonably confident that perhaps within ten years from now I’ll be able to freeze human beings for as long or as short a time as I would like to, and then bring them back to life again in exactly the same state that they were in before they were frozen…just as you can do with animals.W: And what’s the main application of your researchM: I think the main application of this for human beings would be for people with terminal illnesses, such as certain types of cancer, AIDS. We could freeze them, find a cure for the illness and then bring them back to life again and administer the cure.W: I see. Well, this obviously is going to create great debate I would think as to the rights and wrongs of whether we should be actually doing this. What is true about the application of Professor Morgan’s research().
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