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Should everyone be getting more folic acid? That’s the question on a lot of doctors’ minds. Though not as famous as vitamin C, folic acid plays a crucial role in the development of just about every cell in the body. Member of the B-vitamin family, it’s found naturally in orange juice, beans and green vegetables. There is some evidence that folic acid may reduce the risk of heart disease, but it is best known for its role in preventing spinal bifida and other birth defects. Indeed ever since 1998, when the U.S. Food and Drug Administration mandated that it be added to cereal products, the number of so-called neural-tube defects has dropped nearly 20% across America.Now comes word that the vitamin may, just may, help ward off the ravages of Alzheimer’s disease. In a study of more than 1,000 older adults published in the New England Journal of Medicine, researchers at Boston University and Tufts University found that subjects who had high levels of a particular amino acid called homocysteine in their blood were twice as likely to develop Alzheimer’s as those who didn’t. The finding is important because one of the easiest ways to lower homocysteine levels is to get plenty of folic acid.The study, although not definitive, is the strongest evidence to date that homocysteine plays a role in Alzheimer’s. Previous research had found that Alzheimer’s patients often have high levels of the amino acid in their blood-though that could be because folks with Alzheimer’s often don’t eat very well.The new study lays that explanation to rest. As part of the famous Framingham study, which has tracked the development of heart disease among residents of Framingham, Massachusetts, for more than 50 years, researchers in the 1970s started measuring the homocysteine levels of men and women who had not yet developed dementia. Those patients whose homocysteine levels measured over 14 micromoles a liter while they were still healthy were twice as likely to be diagnosed with Alzheimer’s disease later on.That doesn’t mean that if you have high homocysteine levels, you will get Alzheimer’s, or that low homocysteine levels will protect your from dementia. It’s not even certain, warns Dr. Sudha Seshadri, a neurologist at Boston University who led the study, that lowering homocysteine levels will lower the risk of Alzheimer’s. But the case for adding folic acid to your diet is getting better all the time.Of course the best source of any vitamin is a healthy diet. For those of us who still don’t eat our beans and vegetables, most multivitamins contain the recommended daily folic acid dose of 400 micrograms. (Eating four slices of enriched bread gives you the equivalent of roughly 100 micrograms.) There is no risk of overdose, although high levels of folic acid can mask the signs of pernicious anemia in people who have developed the disorder. Folic acid by itself may not keep the doctor away, but there’s no harm trying.1. Which of the following is TRUE according to the passage?2. The word “pernicious” in the last paragraph means( ).3. When did the U.S. Food and Drug Administration mandate that folic acid be added to cereal products?4. The disease of “dementia” (paragraph 4) has something to do with( ).5. Which of the following is NOT true about folic acid?
A rapid means of long distance transportation became a necessity for the United States settlement spread ever farther westward. The early trains were impractical curiosities, and for a long time the railroad companies met with troublesome mechanical problems. The most serious ones were the construction of rails able to bear the load, and the development of a safer, effective stopping system.Once these were solved, the railroad was established as the best means of land transportation. By 1860s there were thousands of miles or railroads crossing the eastern mountain ranges and reaching westward to the Mississippi. There were also regional southern and western lines.The high point in railroad building came with the construction of the first transcontinental system. In 1862 Congress authorized two western railroad companies to build lines from Nebraska westward and from California eastward to a meeting point, so as to complete a transcontinental crossing linking the Atlantic seaboard with Pacific. The Government helped the railroads generously with money and land. Actual work on this project from California used Chinese labor, while the Union Pacific employed crews of Irish laborers. The two groups worked at remarkable speed, each trying to cover a greater distance than the other. In 1896 they met at place called Promontory in what is now the state of Utah. Many visitors came there for the great occasion. There were joyous celebrations all over the country, with parade and the ringing of church bells to honor the great achievement.The railroad was very important in encouraging westward movement. It also helped build up industry and fanning by moving raw materials and by distributing products rapidly to distant markets. In linking towns and people to one another it helped unify the United States.1. The major problems with America’s railroad system in the mid-19th century lay in( ).2. The building of the first transcontinental system( ).3. The best title for this passage would be( ).4. The construction of the transcontinental railroad took( ).5. What most likely made people think about a transcontinental railroad?
Corporations as a group offer a variety of jobs. Most large companies send people to colleges to colleges to interview graduating students with the required academic training. A large university may have more than 500 companies a year knocking on its doors. Big firms are your best place for a job because their normal growth, employee retirements, and turnover create thousands of jobs nationwide each year.Corporations, however, illustrate the rule that the biggest isn’t always the best. Many small firms with just a few hundred employees have positions that may correspond with your profession goals, too. Such firms may not have the time, money, or need to send people around to your college; you’ll probably have to contact them yourself either directly or through an employment agency. Don’t ignore these little companies. Their salaries are usually competitive and the chances for advancement and recognition even stronger than those of a big firm. You could become a big fish in a small pond, reaching a high-level position more quickly than you would if you had climbed the most competitive ladder of a corporate giant.For example, a small company may need a bright engineering, accounting or management graduate who would report directly to the senior vice-president of engineering, the company controller, or the general manager. In larger firms it may take years to reach level and accumulate similar in-depth experience. In addition, responsibilities may come faster in a small firm with less specialization and fewer lower-level employees to receive delegated authority.1. The purpose of the passage is( ).2. Which of the following is TRUE of large corporations?3. The word “Their” (paragraph 2, line 6) refers to( ).4. Which of the following is NOT true of small firm?5. With whom is the passage most probably concerned?
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