Unit 4 Global warming Using language课时作业

　　Ⅰ.单词拼写

　　1．The chart shows an up________(趋势) of meat prices.

　　2．The parents________(记录) every step of their child's development.

　　3．So far Internet has become the main channel through which the computer________(病毒) spread.

　　4．Sometimes an________(附件) with a nice name in your mail can be very dangerous.

　　5．If your computer shows such information, it warns you that you are________(感染)．

　　6．The young teacher infected the whole class with her________(热情)．

　　7．Patience combined with________(勤奋) is necessary to success.

　　8．Soon he was________(淹没，消失) up in the noisy crowd.

　　9．He has finished the reading of the book, but he has not________(消化) it.

　　10．England is________(接壤) on the north by Scotland.

　　【答案】　1.trend　2.documented　3.viruses 4.attachment　5.infected　6.enthusiasm 7．diligence　8.swallowed　9.digested　10.bounded

　　Ⅱ.阅读理解

　　Talking plants might sound like characters in a fairy tale.But recent scientific studies have shown that plants communicate with each other and with other living things in a surprising number of ways.To understand them, scientists say, we just have to learn their language.Farmers are especially interested in what plants have to say.

　　"Plants are able to communicate with all sorts of organisms(有机体)．They can communicate with giant bacteria, with other plants and with insects.They do this chemically，" said Cahill, an Ecology Professor of the University of Alberta in Canada.

Plant scientists are just beginning to understand this chemical "language"．Cahill says studies have shown, for example, that plants can evaluate conditions in their immediate environment and take appropriate actions.Plants have an ability, for example, to signal pain or discomfort caused by anything from temperature extremes to an insect attack.Jack Schultz, a professor of chemical ecology at the University of Missouri says