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更多“2. Taking a plastic forming te…”相关的问题
第1题
A．As soon
B．Ever since
C．So that
D．Now that
第2题
Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A, B, C and D. You should decide on the best choice.
Henry III didn't know much about biology. He went through six wives back in the 1500s, looking for one who could bear him a son. Seientists now know that it's the father's sperm, not the mother's egg, which determines whether a baby is a boy or a girl. And last week researchers at the Genetics and IVF Institute, a private fertility (生育能力) center in Virginia, announced a new technique that will allow parents to choose the sex of their baby-to-be, before it has even been conceived. The scientist used a tiny laser deteetor to measure the DNA in millions of sperm ceils as they pass single file through a narrow tube, like cattle being herded through a corral (牲口栏). In a study published last week, "girl sperm," which has more DNA--the genetic material-- in eaeh cell, was collected, while "boy sperm" was discarded. And when purified girl sperm was used to impregnate (使受孕) a group of mothers, 15 of 17 resulting babies turned out to be girls.
The researchers say that "sex selection" can also double a mother's chance of having a son and can be used to avoid genetic diseases that affect only one gender, such as hemophilia (血友病). But some experts, like New York University fertility specialist Dr. Jamie Grifo, worry that sex selection could lead to a kind of in uteri (子宫) discrimination, especially in cultures where sons are considered superior to daughters. "It's valuing one gender over another," Grifo says. "I don't think that's something we should be doing." So far, patients at the institute have been asking for both boys and girls, in order to "balance" their families. And some ethics experts say that's fine, as long as parents are just looking for a little gender variety. "If you have three boys, and you want a girl," says University of Texas reproductive-law professor John Robertson, "that's not gender bias at all."
The DNA in the sperm cells can be measured ________.
A．in the same way how the cattle are herded
B．when they pass through a tube one behind the other
C．after they pass through a laser tube
D．when they are scanned by a laser detector all at a time
第3题
第4题
An important characteristic of parkour is efficiency. Practitioners move not only as fast as they can, but also in the least energy-consuming and most direct way possible. This characteristic distinguishes it from the similar practice of free running, which places more emphasis on freedom of movements, such as acrobatics. Efficiency also involves avoiding injuries, short and long-term, part of why parkour's unofficial motto is tre et durer(to be and to last).
Tracers claim that parkour also influences one's thought process by enhancing critical thinking skills that allow one to overcome everyday physical and mental obstacles.
There are fewer predefined movements in parkour than gymnastics, as it does not have a list of appropriate "moves." Each obstacle a tracer faces presents a unique challenge on how they can overcome it effectively, which depends on their body type, speed and angle of approach, the physical make-up of the obstacle, etc. Parkour is about training the body mind to react to those obstacles appropriately with a technique that works. Often that technique cannot and need not be classified and given a name. In many cases effective parkour techniques depend on fast redistribution of body weight and the use of momentum to perform. seemingly impossible or difficult body maneuvers at speed. Absorption and redistribution of energy is also an important factor, such as body rolls when landing which reduce impact forces on the legs and spine, allowing a tracer to jump from greater heights than those often considered sensible in other forms of acrobatics and gymnastics.
There are many basic techniques that are emphasized to beginners for their versatility and effective- ness. Most important are good jumping and landing techniques. The roll, used to limit impact after a drop and to carry one's momentum onward, is often stressed as the most important technique to learn. ② Many tracers develop joint problems from too many large drops and rolling incorrectly. Due to large drops
parkour has sometimes received criticism for its questionable safety. Several communities in Great Britain have been warned by law enforcement or fire and rescue of the potential dangers of parkour. Although David Belle has never been seriously injured while practicing parkour, there is no careful study about the health issues of large drops and tracers stress gradual progression to avoid any problems. ③
Parkour participators______.
A．aim to exploit their potential strength
B．move the longest distance they can endure
C．practice prescriptive movements
D．choose different paths to the terminals by themselves
第5题
M: What does it look like I am doing?
W: Well, it looks like you are watching television. But we have an exam tomorrow, so I thought you'd be studying for it and maybe I can study with you.
M: Oh, well, I was just taking a break. The books give me a headache if I work on it too long.
W: I know what you mean. I've been working on it for three hours already.
M: But I can't believe you are coming to me. I mean you do know what I got on the last test, don't you?
W: Yeah, I know. You told me. I just thought two heads might be better than one.
M: That's nice idea. But... you know, I wish I knew that person in our class who got a hundred on the last test. She didn't miss a question. Umm... was it Julie?
W: Oh yeah, Julie! She is a friend of mine. She'd be a big help right now. Why don't I give her a call?
M: What! At this hour? It's already ten thirty.
W: I guess you are tight. But you know what, she owes me a big favor. Let's at least give her a call and see what she says. Maybe going over some of the problems with us would help her review the material.
M: It's worth a try.
(20)
A．The food in the kitchen.
B．The TV Programme.
C．The roommate of the man.
D．The coming exam.
第6题
You are going to read a list of headings and a text about happiness. Choose the most suitable heading from the list A—F for each numbered paragraph (41—45). The first and last paragraphs of the text are not numbered. There is one extra heading which you do not need to use.
A. Extensive applications of haptic technology.
B. Possibilities rendered by haptic mechanisms.
C. The feasibility of extending our senses and exploring abstract universes.
D. An example of the progress in science of haptics.
E. Bringing the potential of our senses into full play.
F. Will haptics step into a bright future?
"OOOF!" Using your mouse, you heave a data file across the screen—a couple of gigabytes of data weigh a lot. Its rough surface tells you that it is a graphics file. Having tipped this huge pile of data into a hopper that sends it to the right program, you examine a screen image of the forest trail you'll be hiking on your vacation. Then, using a gloved hand, you master its details by running your fingers over its forks and bends, its sharp rises and falls. Later you send an E-mail to your beloved, bending to the deskpad to attach a kiss.
(41)______.
The science of haptics (from the Greek haptesthai, "to touch") is making these fantasies real. A few primitive devices are extending human-machine communication beyond vision and sound. Haptic joysticks and steering wheels for computer games are already giving happy players some of the sensations of piloting a spaceship, driving a racing car or firing weapons. In time, haptic interfaces may allow us to manipulate single molecules, feel clouds and galaxies, even reach into higher dimensions to grasp the subtle structures of mathematics.
(42)______.
Most of our senses tire passive. In hearing and vision, for example, the sound or light is simply received and analyzed. But touch is different: we actively explore and alter reality with our hands, so the same action that gathers information can also change the world—to model a piece of clay or press a button, for example. In providing direct contact between people, touch carries emotional impact. And in providing direct contact with the world, it is the sure sign of reality, as in "pinch me—am I dreaming?"
(43)______.
Some small steps have even been taken towards whole-body haptics. Touch Technology of Nova Scotia, Canada, has built a haptic chair. It looks like a full-length lounge chair in a family den, but its surface is studded with 72 "tactors" -pneumatic piston rods, covered with rounded buttons, that can extend about an inch, and can be driven under computer control in any desired sequence and pattern. It could be programmed to imitate a real massage or to function in time to music. According to the manufacturer, that provides a powerful blending of sensations—a long-term goal of virtual reality.
(44)______.
Even at its present crude level, however, haptics can make tangible what once could not be touched or even pictured. To investigate the world of the very small, researchers at the University of North Carolina, Chapel Hill, have developed the nanoManipulator. This adds touch to the technique of scanning probe microscopy, which can image a single atom by monitoring either the electrical current flowing between an extremely fine probe and a surface or the force between them. With the nanoManipulator, researchers can see and manipulate a universe a million times smaller than their own, to study viruses and tiny semiconducting devices. If the force feedback can be made sensitive enough, it may be possible to push molecular keys into specific molecular locks, to custom-design drugs or assemble silicon parts into intricate nanomachines. With other interfaces, there is no reason we shouldn't also be able to touch the very large-clouds, ocean
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