For Superposition, it is required that only one independent source be considered at a time; two or more independent sources may not be considered simultaneously.

相似题目

• It is not advisable to use nylon for alongside towing because it（）.

  A . is too expensive for everyday towing usage B . binds on the cleats C . parts too readily D . strethes too much

  查看最佳答案

• A storm is forecast for the area where your vessel is moored. For its safety you should put （）.

  A . more slack in the mooring lines B . a strain on the mooring lines C . chafing gear on the mooring lines D . grease on the mooring line

  查看最佳答案

• It is（）that he has to ask for help.

  A . so a big job B . a so big job C . a such big job D . such a big jo

  查看最佳答案

• Obviously, for a given fuel oil, its pour point is （） its cloud point.

  A . lower than B . higher than C . as same as D . better tha

  查看最佳答案

• The swimming pool is so（）that it's safe for small children.

  A . stable B . smooth C . superficial D . shallow

  查看最佳答案

• Retirement should be the reward for a lifetime of work.It is widely viewed as a sort of punishment.It is a punishment for growing old.

  查看最佳答案

• How much is the stallholder asking for it?

  查看最佳答案

• It is a very big opportunity for human; the challenge is _______ it wisely.

  查看最佳答案

• Which could be the responses for “How is it going?”

  查看最佳答案

• It is too expensive. Can you let me have it for____ $20.

  查看最佳答案

• Jingdezhen is famed for its silverware production . （ ）

  查看最佳答案

• The Palace R estaurant is famous for its friendly and efficient __________.

  查看最佳答案

• 3.For the young, the hunger for knowledge is strong, and it is not confined to any time or place.

  查看最佳答案

• Shopping for clothes is not the same experience for a man __________ it is for a woman.

  A.as B.than C.that D.when

  查看最佳答案

• What is IKEA's main policy for educating its staff？

  A．It produces educational videos and brochures. B．It holds special training sessions for managers. C．It encourages regular meeting to discuss culture.

  查看最佳答案

• He is opposed to the project for the reson_______ it is not prcticl for the time being.whyB．wh. He is opposed to the project for the reson_______ it is not prcticl for the time being.why B．wht C．becuse D．tht

  A．why B．what C．because D．that

  查看最佳答案

• Magdalena Smith thinks it is important for______.

  A．students to get good jobs B．students to participate in music, dramatics, and sports C．students to compete more for grades D．educators to have more control over grades

  查看最佳答案

• Mark Twain once observed that giving up smoking is easy. He knew, because he'd done it hundreds of times himself. Giving up for ever is a trifle more difficult, apparently, and it is well known that it is much more difficult for some people than for others. Why is this so？

  Few doctors believe any longer that it is simply a question of will power. And for those people that continue to view addicts as merely "weak", recent genetic research may force a rethink. A study conducted by Jacqueline Vink, of the Free University of Amsterdam, used a database called the Netherlands Twin Register to analyze the smoking habits of twins. Her results, published in the Pharmacogenomics Journal, suggest that an individual's degree of nicotine dependence, and even the number of cigarettes he smokes per day, are strongly genetically influenced. The Netherlands Twin Register is a voluntary database that contains details of some 7,000 pairs of adult twins (aged between 15 and 70) and 28,000 pairs of childhood twins. Such databases are prized by geneticists because they allow the comparison of identical twins (who share all their genes) with fraternal twins (who share half). In this case, however, Dr. Vink did not make use of that fact. For her, the database was merely a convenient repository of information. Instead of comparing identical and fraternal twins, she concentrated on the adult fraternal twins, most of whom had completed questionnaires about their habits, including smoking, and 536 of whom had given DNA samples to the register. The human genome is huge. It consists of billions of DNA "letters", some of which can be strung together to make sense (the genes) but many of which have either no function, or an unknown function, To follow what is going on, geneticists rely on markers they have identified within the genome. These are places where the genetic letters may vary between individuals. If a particular variant is routinely associated with a particular physical feature or a behavior. pattern, it suggests that a particular version of a nearby gene is influencing that feature or behavior. Dr. Vink found four markers which seemed to be associated with smoking. They were on chromosomes 3, 6, 10 and 14, suggesting that at least four genes are involved. Dr. Vink hopes that finding genes responsible for nicotine dependence will make it possible to identify the causes of such dependence. That will help to classify smokers better (some are social smokers while others are physically addicted) and thus enable "quitting" programs to be customized. Results such as Dr. Vink's must be interpreted with care. Association studies, as such projects are known, have a disturbing habit of disappearing, as it were, in a puff of smoke when someone tries to replicate them. But if Dr. Vink really has exposed a genetic link with addiction, then Mark Twain's problem may eventually become a thing of the past. Mark Twain is mentioned in the passage in order to show that A．he is a man with very Strong will power. B．it is easy to give up smoking temporarily. C．famous writers are often heavy smokers. D．only few people have his determination.

  查看最佳答案

• It is he that I am looking for.（）

  对 错

  查看最佳答案

• 三句英语句子的意思. Is it okay for me to come on Wednesday? Is it okay for me to hand in my paper tomorrw? Is it okay for me to ask her out?

  查看最佳答案

• 修辞：“Distressed Areas”, it is an（）for slums or ghettos

  A．simile B．understatement C．metaphor D．exaggeration

  查看最佳答案

• Our restaurant is famous for its___（）

  A．effect B．pay C．seafood D．reward

  查看最佳答案

• It is（)（child)to run into danger for nothing.

  查看最佳答案