Pipes made of plastic are now widely used in building as they are light and do not become （）in water.

As computers evolve, they have become Smaller and smaller, while speed and(66)have increased tremendously.

Sam Scott and his sister Ann are students． Sam(11) school by bus， and Ann does， too．Some of(12)walk(走) to school．Sam and Ann (13) at four o'clock in the af- ternoon． They (14) before dinnerc晚饭前)，and they watch TV after dinner． They u- sually(15 early(早)．Sam and Ann (16) three meals(饭) a day :breakfast， lunch and dinner． They．have breakfast at home．(17) they have lunch (18) school． They often eat dinner at home．Mr Scott (19) from( 20) at five and they have dinner at six．( )11．

As time went by, computers became smaller and more powerful, and they became “personal” too, as well as institutional, with display becoming sharper and storage _____ increasing.

●The (75)is designed specifically as a security system for preventing unauthorized communications between one computer network and another computer network.

Computer hardware engineers research, design, develop, and test computer hardware and supervise its manufacture and(73). Hardware refers to computer(74), circuit boards, computer systems, and related equipment such as keyboards, modems, and printers.

（） allows the engine to be placed wherever is most suitable, as they no longer have to be aligned with reduction gearing and shafting as is the case with conventional installations.

Computers and mobile phones, playgh they are indeed making our life__________ and more ________have reduced the need for face-to-face cotyr unication.

［A］ As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic potential.

Practice 4　 Read the following text(s) and write an essay to　 1) summarize the main points of the text(s),　 2) make clear your own viewpoint, and　 3) justify your stand.　 In your essay, make full use of the information provided in the text(s). If you use more than three consecutive words from the text(s), use quotation marks (“ ”).　 You should write 160—200 words on the ANSWER SHEET.　 The information and computer technologies have boosted the efficiency and convenience of people’s work and study. Their application in school education has provided teachers and students with new approaches to knowledge and information. There is a heated discussion about whether computers will replace teachers. The following are the supporters’ and opponents’ opinions.　 Supporters:　 With the advanced computer and Internet, children can get the learning material whenever they want.　 Online teaching is becoming more and more popular that students can get planned lessons online. After each class, there is homework for them to do. Both the learning and practice can be done on computers.　 From computers students can learn something that they are interested in so that they won’t be restricted to the subjects that they are taught at school. Therefore, students will have the opportunity to achieve an all-around development.　 Opponents:　 Students need to communicate with teachers and get instructions from them whenever they have troubles in their study. Computers are only cold devices that will affect children’s ability to have face-to-face communication.　 Education is not only about imparting the knowledge, but also being a useful person. So students need to learn some useful values to be a good person which sometimes cannot be easily learned from computers.　 Children who use computer will learn to communicate with machines instead of people. There is a risk that they will be a generation of social illiterates.

All computers need some sort of(71)(OS). Tile majority of modem home computers use some form. of Microsofts OS. The original Microsoft OS was called DOS though most computers use Windows. Windows comes in various versions beginning with(72)x then 95, 98, ME and currently XP. A few computers use IBMs O/SApples Mac uses their own OS beginning with OS I though most modem Macs use version x or x. Apples latest version is OS 10.x. In the past large companies and institutions would have an OS design exclusively for them but as the Commercial OS become more sophisticated the benefits of this practice is becoming less apparent. Some computer professionals,(73)(ISP)and(74)computer users use an OS such as UNIX(or a variant such as Linux), Windows NT or 2000(Win2k)or one of the other network or(75)based OS.