题目内容
The great advance in rocket theory 40 years ago showed that liquid-fuel rockets were far superior in every respect to the skyrocket with its weak solid fuel, the only kind of rocket then known. However, during the last decade, large solid-fuel rockets with solid fuels about as powerful as liquid fuels have made their appearance, and it is a favorite layman's question to inquire which one is "better". The question is meaningless; one might as well ask whether a gasoline or a diesel engine is "better". It all depends on the purpose. A liquid-fuel rocket is complicated, but has the advantage that it can be controlled beautifully. The burning of the rocket engine can be stopped completely: it can be re-ignited when desired. In addition, the thrust can be made to vary by adjusting the speed of the fuel pumps. A solid-fuel rocket, on the other hand, is rather simple in construction, though hard to build when a really large size is desired. But once you have a solid-fuel rocket, it is ready for action at very short notice. A liquid-fuel rocket has to be fueled first and cannot be held in readiness for very long after it has been fueled. However, once a solid-fuel rocket has been ignited, it will keep burning. It cannot be stopped and re-ignited whenever desired (it could conceivably be stopped and re-ignited after a pre-calculated time of burning has elapsed) and its thrust cannot be varied. Because a solid-fuel rocket can be kept ready for a long time, most military missiles employ solid fuels, but manned space flight needs the fine adjustments that can only be provided by liquid fuels. It may be added that a liquid-fuel rocket is an expensive device; a large solid-fuel rocket is, by comparison, cheap. But the solid fuel, pound per pound; costs about 10 times as much as the liquid fuel. So you have, on the one, hand, an expensive rocket with a cheep fuel and on the other hand a comparatively cheap rocket with an expensive fuel.
The author feels that a comparison of liquid and solid-fuel rockets shows that ______.
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The Value of Writing Well
It's that time of year again. No, not "the holiday season". I mean, it is holiday time, but for professors it doesn't start feeling like holiday time until final grades are in and the books are closed on another semester. No, for me, it's paper-grading time, the time of year when I'm reminded over and over of the importance of good writing skills--and of their rarity.
The ability to write well is not a gift. Sure, the special something that sets apart a Tolstoy or Shakespeare or Salman Rushdie or Isabel Allende is a gift, a talent born of disposition, experience, and commitment. But just to be able to communicate clearly with the written word takes no special talent; it's a skill like any other.
Well, not exactly like any other. Because the words we use to write with are the same words we use to think with, learning to write well has ramifications that go beyond the merely technical. As we improve our writing ability, we improve our ability to think--to build an argument, to frame. issues in compelling ways, to weave apparently unrelated facts into a coherent whole.
And despite the recurring hand-wringing and chest-beating about the "end of literacy" and the "death of the printed word", the reality is that we write more than ever these days. While it's a rare person who sits down with pen and paper in hand and writes a letter to a friend or loved one, we pour emails into the ether at an astounding rate. We text message, tweet, instant message, blog, comment, and otherwise shoot words at each other in a near-constant flow of communication. We annotate group portraits, LOL-ify cat pictures, and tag.., well, everything. At work, we write letters, proposals, PowerPoint presentations, Business requirement documents, memos, speeches, mission statements, position papers, operating procedures, manuals, brochures, package copy, press releases, and dozens of more specialized types of documents.
We are, it seems, writing creatures. Homo scribus, if you will.
It's no wonder that Businesses repeatedly cite "communication skills" as the single most desirable trait in new employees. The kicker, though, is that we are as a society incredibly bad at writing. Public schools do a poor job of teaching students how to write well-they barely manage to instill the basic rules of grammar and the miserable 5-paragraph essay, let alone how to write with style. and verve, how to put together an argument that moves steadily from one point to the next to persuade a reader of some crucial point, how to synthesize ideas and data from multiple sources into something that takes those ideas one step further.
It's not just the teachers' fault. Teachers do the best they can with what they're given, and all too often what they're given is inadequate resources with which to teach classrooms full of unmotivated students who could care less about writing. Add to that the requirements of mandatory nation-wide tests that reward conformity, not creativity, and the threat of punishment for any school whose students fail to fall within the fairly rigid boundaries of the test's requirements, and you've got a pretty bad situation all around for instilling in students the power to write well.
That is, alas, a great disservice. Being able to write well vastly improves students'-and others'-potential for success, regardless of the field they find themselves in. As I've already mentioned, people who write well tend to be better able to think through problems and tease out patterns in outwardly dissimilar situations. More importantly, people who write well have the opportunity to make a mark in the world, because their best ideas aren't trapped in their own minds for lack of a means of expression.
This is true whether you're a CEO or a janitor, a marketing expert or an Emergency Medical Technician. The skills
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