福建省2014高考英语一轮复习作业手册（15）（含解析）新人教版_高考复习指南

福建省2014高考英语一轮复习作业手册（15）（含解析）新人教版

　　福建省2014高考英语（新人教版）一轮复习作业手册（15）附详细解析

　　课时作业(十五)　[必修3　Unit 5 Canada—“The True North”](限时：45分钟)Ⅰ.完形填空

　　Generally，a computer is any device that can perform numerical calculations.__1__，however，the term usually refers to an electronic device that can __2__a series of tasks according to a __3__set of instructions.

　　In 1953 there were only about 100 computers in use in the __4__world.Today hundreds of millions of computers are being used in homes，schools，businesses，government offices，and universities for almost every __5__purpose.

　　Modern desktop personal computers，or

　　PCs，are many times more __6__than the huge，milliondollar business computers of the 1960s and 1970s.Most PCs can perform from 400 million to several billion __7__per second.These computers are used not only for household __8__and personal entertainment，but also for most of the automated tasks __9__by small businesses.The fastest desktop computers are called workstations，and they are __10__used for scientific，engineering，or advanced business __11__.

　　The speed and power of supercomputers，the fastest class of computer，are almost beyond human comprehension，and their

　　__12__are continually being __13__.The fastest of these machines can perform more than 7 trillion and theoretically can run more than 12 trillionoperations per second and can store 6 trillion characters in its memory，allowing it to do the work of thousands of PCs.Supercomputers __14__these speeds through the use of several advanced engineering techniques.Because they can cost billions of dollars and because they can be large enough to cover the size of two basketball courts—supercomputers are used __15__by government agencies and large research centers.