对 * * 狭窄描述的是（）。 A.病因可分为先天性，炎症性，外伤性和医源性 B.骨盆骨折

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 ply 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 p 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

设N_A为阿佛加德罗常数，下列叙述错误的（　　）

A．46g二氧化氮与四氧化二氮的混合气体中的原子数大于3N_A

B．28g乙烯、丙烯、丙烷的混合气体中的碳原子数小于2N_A

C．1mol/L 500mL氯化镁溶液中的镁离子数小于0.5N_A

D．标态下，11.2L三氧化硫中所含的氧原子数大于1.5N_A

你是新上任的副镇长，根据镇政府的决议给下属安排工作，在会上同时有几个下属提出理由不能执行，使你很难堪你该怎么办？

香附、乌药、木香具有的共同功效是（）。

A.降逆止呃

B.疏肝解郁

C.行气止痛

D.行气导滞

E.消肿散结

本地小区载波不可用时，审计响应消息中不会上报该载波，小区也无法建立。请列出几种常见影响本地小区载波状态的几个因素，并给出简单解决办法。（Iub口传输正常）。