题目内容
Passage Five
From the beginning rivers have played an important part in the life of man. Man of the earliest times used the rivers as a means of traveling. Today rivers still serve as a great waterway for the transport and people.
In ancient times, man settled near rivers or on river banks and built up large empires.
Water is the Nature's most precious gift to man. Man needs water to irrigate his crops, to cook and to wash. In nations all over the world rivers mean life and wealth. They feed and clothe the nations around them.
Water is also a source of energy and power. Man constructs huge dams across the river to control the water for irrigation and get the energy needed to drive generators. The electrical power is then directed to homes, cities, factories and television stations.
Man uses water each day. His main source of water comes from reservoirs, which in turn get their water from the rivers.
Rivers also bring down soil and minerals from the mountains and deposit them on the plains building up rich river deltas for raising plants and crops. Fresh water life in rivers or in lakes fed by them provide man with food.
In a small way rivers help to keep man in good health and provide for his amusements. Various forms of water sports keep man strong and healthy.
Rivers have run on this earth long before man. Man's future ability to live is uncertain, but rivers will flow on forever.
52. Rivers have been important to man______.
查看答案
搜索结果不匹配？点我反馈
更多问题
Judge: And where have you stolen these things？
Thief: Oh, (57) .
Passage Four
Archimedes was a famous Greek mathematician and scientist. He was born around 287 BC and he died in the year 212 BC.
Archimedes is most well-known for one specific idea that he came up with. "Archimedes's Principle" states that a solid object which is immersed in a liquid is pushed up by a force which is equal to the weight of the water that the object moves. For example, if you put a piece of wood and a piece of gold the same size in water, only the wood will float. Both the wood and gold move the same amount of water, but the wood weighs less than this water, while the gold weighs more.
It is believed that Archimedes discovered this principle when the king of Syracuse asked him to solve a problem. The king wanted to know if his crown was pure gold or a mixture of gold and silver. The king, of course, did not melt his crown to find out. The idea came to Archimedes as he lowered himself into his bath. He noticed how the water spilled out of the tub. He decided to use the same idea for the crown. He knew that a gold crown immersed in water would weigh more than one made of silver. The experiment was done and the goldsmith was proved guilty of trying to cheat the king.
48. A good title for the selection is______.
What does the passage tell us？
It's an annual back-to-school routine. One morning you wave goodbye, and that (21) evening you're burning the mid-night oil in sympathy. In the race to improve educational standards, (22) are throwing the books at kids. (23) elementary school students are complaining of homework fatigue. What's a well-meaning parent to do？
As hard as (24) may be, sit back and chill experts advise. Though you've got to get them to do it, (25) helping too much, or even examining answers too carefully, you may keep them (26) doing it by themselves. "! wouldn't advise a parent to check every 27 assignment," says psychologist John Rosemond, author of Ending the Tough Homework, "There's a (28) of appreciation for trial and error. Let your children (29) the grade they deserve."
Many experts believe parents should gently look over the work of younger children and ask them to rethink their (30) . But "you don't want them to feel it has to be (31) ," she says.
That's not to say parents should (32) homework—first, they should monitor how much homework their kids have. Thirty minutes a day in the early elementary years and an hour in (33) four, five, and six is standard, says Rosemond. For junior-high students it should be" (34) more than a hour and a half," and two for high school students. If your child consistently has more homework than this, you may want to check (35) other parents and then talk to the teacher about reducing assignments.
21.
微信支付 
支付宝支付