您正在看的高中三年级是:Feed the world。 her was forced to give up smoking because of his illness.

　　因为生病，我父亲不得不戒烟.

　　2)cash crop经济作物(a crop that is sold abroad to provide foreign exchange)，或(a crop produced for sale rather than for use by the grower)

　　Cotton is a cash crop in the South.

　　在南方，棉花是经济作物.

　　They raise potatoes to eat，but corn is their cash crop.

　　3)pay off还清债务(discharge a debt completely)

　　It took him five years to pay off his debts.

　　他用了5年的时间还清了债务.

　　19.This grain could be used to feed humans，rather than animals.

　　这些谷物本来是可以供人食用的，而不是喂牲口.

　　rather than而不是

　　John ought to go rather than Jean.

　　应该去的是约翰，而不是吉恩.

　　He is a worker rather than a student.

　　与其说他是学生，不如说他是工人.

　　20 ，it makes very good sense to keep sheep or goats.

　　……，饲养绵羊或山羊倒是有意义的.

　　make sense有意义;讲得通

　　She doesn’t talk much，but what she says makes sense.

　　她讲话不多，但言之有理.

　　典型例题

　　例1.Paper money was in ___________ use in China when Marco Polo visited the country in __________ thirteenth century.

　　A.the;不填

　　B.the;the

　　C.不填;the

　　D.不填;不填

　　此题第一空in use是习语，表示在“在运用”，不加冠词，而第二空“13世纪”前当然要加定冠词“the”.因此，本题答案为C.

　　例2.It was only when I reread his poems recently _________ I began to appreciate their beauty.

　　A.until B.that C.then D.so

　　此题为强调句型，所以本题应选B.

　　例3.Carot said the work would be done by October，_____________personally 1 doubt very much.

　　A.it B.that C.when D.which

　　此题是考查由which引导的非限制性定语从句，而that不能引导非限制性定语从句，故本题要选D.