三.课文详解

　　The Atlantic Ocean (链接图片大西洋)

　　The Atlantic Ocean is one of the oceans that separate the Old World from the New. ①For centuries it kept the Americas from being discovered by the people

of Europe. ②

　　Many wrong ideas about the Atlantic made early sailors unwilling to sail far out into it. ③ One idea was that it reached out to "the edge of the world. " Sailors were afraid that they might sail right off the earth. Another idea was that at the equator the ocean would be boiling hot. ④

　　The Atlantic Ocean is only half as big as the Pacific, but it is still very large. ⑤It is more than 4,000 miles (6,000 km) wide where Columbus crossed it. ⑥Even at its narrowest it is about 2,000 miles (3,200 km) wide. ⑦This narrowest place is between the bulge of south America and the bulge of Africa.

　　Two things make the Atlantic Ocean rather unusual. For so large an ocean it has very few islands. ⑧Also, it is the world's saltiest ocean.

　　There is so much water in the Atlantic that it is hard to imagine how much there is. But suppose no more rain fell into it and no more water was brought to it by rivers. ⑨It would take the ocean about 4,000 years to dry up. ⑩On the average the water is a little more than two miles (3.2 km) deep, but in places it is much deeper. The deepest spot is near Puerto Rico. This "deep" measures 30,246 feet—almost six miles (9.6 km).

　　One of the longest mountain ranges of the world rises from the floor of the Atlantic. This mountain range runs north and south down the middle of the ocean. The tops of a few of the mountains reach up above the sea and make islands. The Azores are the tops of peaks in the mid-Atlantic mountain range.

　　Several hundred miles eastward from Florida there is a part of the ocean called the Sargasso Sea. Here the water is quiet, for there is little wind. In the days of sailing vessels the crew were afraid they would be becalmed here. Sometimes they were.

　　Ocean currents are sometimes called "rivers in the sea." One of these "rivers" in the Atlantic is called the Gulf Stream. It is a current of warm water. Another is the Labrador Current — cold water coming down from the Arctic. Ocean currents affect the climates of the lands near which they flow.

　　The Atlantic furnishes much food for the people on its shores. One of its most famous fishing regions, the Grand Banks, is near New- foundland.

　　Today the Atlantic is a great highway. It is not, however, always a smooth and safe one. Storms sweep across it and pile up great waves. Icebergs float down from the Far North across the paths of ships.

　　We now have such fast ways of traveling that this big ocean seems to have grown smaller. Columbus sailed for more than two months to cross it. A fast modern steamship can make the trip in less than four days. Airplanes fly from New York to London in only eight hours and from South America to Africa in four!

　　课文详解：

　　1.one of +复数名词+定语从句中，定语从句一般被看作修饰复数名词，从句中谓语动词用复数形式。

　　e.g. This is one of the best books that have appeared this year.这是今年出现的最好的小说之一。

　　注意：如果出现the only one of +复数名词+定语从句时，定语从句应该看作修饰的是单数名词。e.g. He was the only one of the boys who was given a prize.他是这些孩子中唯一受到奖励的。

　　2.此句中keep … from +v.ing 是一个习惯用法，表示“使…不…”。例：You must keep the children from treading on the grass. 您一定别让孩子们践踏草坪。

　　类似用法：stop … from doing sth. 阻止某人做某事； prevent … from doing sth. 阻止某人做某事。此句中being discovered 是discover 的动名词被动形式，意思是“被发现”。

　　3.make sb. do sth.:使役动词make+人+(省略了to)动词原形，e.g. She made the baby take a nap.她让孩子睡个午觉。注意：make如果在用法上出现了被动语态形式，用法则变成了be made to do，e.g. She was made to work.她被要求去上班。此类使役动词还包括get, have, let, help+sb.+do。

　　4. 此句是复合句。that at the equator the ocean would be boiling hot 是表语从句。其中boiling 是现在分词作定语修饰hot .

　　5. as+adj./adv.+as:否定形式为not as/so+adj./adv.+as和…一样…

　　e.g. I am as tall as Yaoming.我和姚明一般高。

　　It isn’t so big as you think it is.它没有你所想象的那么大。

　　有时在该结构前加表示半数或倍数的词，如half, twice, our times…如课文中该句。

　　6.此句中it 是形式主语，真正的主语是where Columbus crossed it.

　　7.表示长、宽、高时的结构为数量词+adj. e.g. Our classroom is 25 meters wide. My brother is 200 centimeters tall.

　　8.so +adj修饰单数名词时，不定冠词应放在adj.与n.之间。

　　e.g. He is not so clever a boy as his brother.他不如他哥哥聪明。

　　few的用法需注意：a few/few+可数名词(复数)；a little/little+不可数名词，另外意思上也有所区别，a few/a little代表有一些/有一点儿，e.g. a few books/a little water；few/little代表是几乎没有，e.g. few books/little water。

　　9.so+adj./adv.+that…:如此…以至于…；such+n./n.phrase+that…

　　e.g. He is so clever that his teacher often praise him in class.他太聪明了，以至于他的老师经常在班里表扬他。

　　e.g. She is such a pretty girl that everyone here likes her.

　　10.It takes time+不定式句型：某人花费多少时间去干某事。

　　e.g. It took me five years to study cooking.学烹饪花了我五年时间。

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