2020-11-06 英语知识


  How the Hawaiian Is lands Were Built

  Volcanoes have been erupting on the earth for millions of years.More than five hundred still erupt today.These are called active volcanoes.Volcanoes are located in belts or chains.They are found where the earth's crust is weak.The weak spots let the hot rock escape when the volcano erupts.

  Many volcano belts are mountain ranges along the edges of continents.One belt runs along the western coast of South America up through the western part of the United States.Other volcanoes are found in ocean basins.

  About three-fifths of all active volcanoes in the world are in the Pacific Ocean.Many of these volcanoes erupt under the water.The Hawaiian Islands were built by volcanoes that began erupting under water and finally reached the surface of the ocean.






  Diamonds in the United States

  Most of the world's diamonds come from Africa,but there is one place in the United States where they are found.It is near Murfreesboro,Arkansas.

  Diamonds were first found near Murfreesboro in 1906.About fifty thousand diamonds have come from this field.One forty-caratdiamond was the largest ever found in North America.But most of the stones were too small to make mining worthwhile.Soon all mining stopped there.Today a visitor to Murfreesboro can hurt for diamonds himself.

  A few diamonds have been found in sand and gravel along the Great Lakes,too.But none of these were in their original blue ground.They may have been formed far to the north and carried south by the last great glaciers.






  The Three Ways of Man to Preserve Meat

  Finding enough meat was a problem for primitive man.Keeping it for times when it was scarce was just as hard.Three ways were found to keep meat from spoiling:salting,drying,and freezing.

  People near salty waters salted their meat.At first they probably rubbed dry salt on it,but this preserved only the outside.Later they may have pickled their meat by soaking it in salt water.

  In hot,dry lands,men found that they could eat meat that had dried while it was still on the bones.They later learned to cut meat into thin strips and hang it up to dry in the hot air.

  Men in cold climates found that frozen meat did not spoil.They could leave their meat outside and eat it when they pleased.







  Earthworms that Help Improve the Soil

  The earthworm is a useful animal.Out of the ground,it is food for other animals.In the ground,it makes rich soil for fields and gardens.

  Earthworms dig tunnels that loosen the soil and make it easy for air and water to reach the roots of plants.These tunnels help keep the soil well drained.

  Earthworms drag dead leaves,grass,and flowers into their burrows.When this plant material decays,it makes the soil more fertile.

  No other animal is so useful in building up good topsoil.It is estimated that in one year fifty thousand earthworms carry about eighteen tons of fine soil to the surface of an acre of land.One worm may add three quarters of a pound of earth to tho topsoil.







  Who First Made Ice Cream

  Most Americans think that ice cream is as American as baseball and apple pie.But ice cream was known long before America was discovered.

  The Roman emperor Nero may have made a kind of ice cream.He hired hundreds of men to bring snow and ice from the mountains.He used it to make cold drinks.Traveler Marco Polobrought back recipes for chilled and frozen milk from China.

  Hundreds of years later,ice cream reached England.It is said that King Charles Ienjoyed that treatvery much.There is a story that he bribed his cook to keep the recipe for ice cream a royal secret.

  Today ice cream is known throughout the world.Americans alone eat more than two billion quartsa year.







  The Necktie through Thick and Thin

  From hat to shoes,men's clothes are useful.Only one piece of clothing is worn just for decoration.It is the necktie,or cravat.The necktie is left over from the time when men wore ruffles,ribbons,and tassels.

  Beau Brummel was an Englishman of the early 1800's.He was famous for his fancy clothes.The story is told that he used to invite guests just to watch him knot his white cravat.

  Now,perhaps,even the necktie is going out of style.It has been getting smaller and smaller for hundreds of years.It started out as a piece of lace and turned into a silk bow.Then it became a triangle that was tied around the neck.Now many neckties are no wider than a piece of string.