With fifteen years Britain and other nations should be well on with the building of huge industrial complexes for the recycling of waste. The word rubbish could lose its meaning because everything which goes into the dumps (垃圾堆) would be made into something useful. Even the most dangerous and unpleasant wastes would provide energy if nothing else.
　　The latest project is to take a city of around half a million inhabitants and discover exactly what raw materials go into it and what go out. The aim is to find out how much of these raw materials could be provided if a plant for recycling waste were built just outside the city. This plant would recycle not only metal such as steel, lead and copper, but also paper and rubber as well.
　　Another new project is being set up to discover the best ways of sorting and separating the rubbish. When this project is complete, the rubbish will be processed like this: First, it will pass through sharp metal bas which will tear open the plastic bags in which rubbish is usually packed; then it will pass through a powerful fan to separate the lightest elements from the heavy solids; after that grounders and rollers will break up everything that can be broken. Finally, the rubbish will pass under magnets (磁铁), which will remove the bits of iron and steel; the rubber and plastic will then be sorted out in the final stage.
　　The first full-scale giant recycling plants are perhaps fifteen years away. Indeed, with the growing cost of transporting rubbish to more distant dumps, some big cities will be forced to build their own recycling plants before long.

　　21. The phrase “be well on with...” (Para. 1, Line 1) most probably means ________.
　　A) have completed what was started
　　B) get ready to start
　　C) have achieved a great deal in
　　D) put an end to（A）

　　22. What is NOT mentioned as a part of the recycling process described in Paragraph 3?
　　A) Breaking up whatever is breakable.
　　B) Sharpening metal bars.
　　C) Separating light elements from the heavy ones.
　　D) Sorting out small pieces of metal.（B）

　　23. What’s the main reason for big cities to build their own recycling plants?
　　A) To deal with wastes in better way.
　　B) To protect the environment from pollution.
　　C) To get raw materials locally.
　　D) To get big profits from those plants.（A）

　　24. The first full-scale huge recycling plants ________.
　　A) began to operate fifteen years ago
　　B) will probably take less than fifteen years to build
　　C) will be built fifteen years later
　　D) will probably be in operation in fifteen years（C）

　　25. The passage is mainly about ________.
　　A) a cheap way to get energy
　　B) the location of recycling plants
　　C) new ways of recycling wastes
　　D) the probably of city environment（C）