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

　　The Atlantic Ocean is only half as big as the pacific, but it is still very large. It is more than 4,000 miles (6,000 km) wide where Columbus crossed it. Even at its narrowest it is about 2,000 miles (3,200 km) wide.

　　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 and no more water was brought to it by rivers. It would take the ocean about 4,000 years to dry up. On the average the water is a little more than 2 miles (3.2 km) deep, but in some places it is much deeper. The deepest spot is near Puerto Rico. This "deep" measures 30,246 feet --- almost six miles (9.6 km).

　　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. 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 travelling 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!

1. From the third paragraph, we can learn that ______ .

A. the Atlantic will dry up in 4,000 years' time

B. no river flows into the Atlantic ocean　　　

C. it's hard to imagine how much water there is in the Atlantic ocean

D. the Ocean floor is rather flat

2.Suppose it's February 27th, 2000. You take a steamship to cross the Atlantic to North America, when will you probably get there?

A. On March 2nd　         B. On March 3rd 　　

C. On February 28th 　　　  D. In eight hours' time

3. What can you learn from the last paragraph of the passage ?

A. The Atlantic has grown smaller than it used to be.

B. The Atlantic had grown wider than it used to be.

C. Fast ways of travelling make the ocean grow smaller.

D. Fast ways of travelling make the ocean seem to grow smaller.

If you’re training for a marathon , a proper plan for water intake (摄入) is important. Of course, there’s the risk of dehydration (脱水). But athletes now know they can also get into trouble by drinking too much. Too much water intake can lower levels of sodium (钠) in the blood . The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research.

Experts advise long distance runners to replace the liquids they sweat out. Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight.

One technique for deciding how much water you need is to get the exact numbers. Runners have to weight themselves before and after a run to determine how much water they’ve lost. If their weight drops by more than 2 percent, they have not drunk enough water.

Hyponatremia occurs when runners drink so much water that blood salt levels drop off. A study published last year tested 488 runners who completed the Boston Marathon and found 13 percent of them had dangerously low blood salt levels. The first sign that runners may notice is slightly swelling in the hands. They can’t get their rings off, and then they might feel sick. They may not remember where they are. In fact, most runners get enough salt to get back to normal levels by eating just one meal after a run. Contrary to the old advice that runners should drink as much as they can to prevent dehydration , the new research has shown that the body is a remarkable machine that actually tells you via thirst when you need water .

56. The author of this passage is primarily concerned with            .

 A. the signs and treatment for dehydration

 B. the long distance runners who need help

 C. how to manage water intake during a marathon

 D. a 28-year-old woman who died after a Boston Marathon

57. Why do runners have to weigh themselves before and after a run ?

 A. They can improve their performance in a run.

 B. They can learn how much salt there is in the blood.

 C. They can know the quantity of water they’ve lost during a run.

 D. They can decide what kind of water they should take during a run.

58. What conclusion can we draw from the passage ?

 A. Taking much salt during a run can avoid selling in the body.

 B. Either too much or too little of water intake is harmful.

 C. A rich meal is helpful to our performance in a run.

 D. We should take enough salt during a run.

59．According the passage, which of the following statements is correct ?

 A. Too much water intake→blood sodium levels ↓→dehydration.

 B. Too much water intake→blood salt levels ↓→hyponatremia .

 C. No water intake→blood sodium levels↑→hyponatremia .

 D. No water intake →blood salt levels ↓→hyponatrenmia .

They believe that there is __________ in the world.

A. no such a car            B. no such car     C. not such cars     D. not such car

They believe that there is __________ in the world.

A. no such a car            B. no such car     C. not such cars     D. not such car

They believe that there is __________ in the world.

A. no such a car            B. no such car     C. not such cars     D. not such car