题目内容
13．He was doing his homework when someoneknocked （knock）at the door．分析 当有人敲门时，他正在做作业．
解答 答案：knocked．
根据He was doing his homework when someone--（knock）at the door．可知当有人敲门时，他正在做作业．这里根据 was doing 可以判断用的是过去进行时，when引导的句子主句用过去进行时，从句用一般过去时．故填knocked．
点评 考查单词填空．准确的翻译句意及分析句子结构、时态、固定搭配等是关键，然后再用合适的形式完成句子．
练习册系列答案
相关题目
1．Did you know that 11，000people die every day from smoking？Did you know that people die every day from breathing smoke （41）A other people's cigarettes（香烟）？
Tobacco（烟叶） smoke has 43ingredients（成分） that may （42）C cancer．If smokers had learned these（43）A when they were young，they probably would never have started smoking．
Most smokers try （44）B first cigarette when they are teenagers．Often，they start smoking because they think that it makes them look more （45）D．Sometimes they start smoking because their friends tell them that it's cool．If teenagers are told that half of them will die before the age of 65from smoking cigarettes，how can they still think it's cool to smoke？
One of the biggest problems is cigarette advertisements．Tobacco companies （46）A tell the truth to teenagers（青少年） about cigarettes．After watching the advertisements on TV or looking at the posters in which people ride horses or play in a rock band，young people often think that smoking（47）C be cool．
Sadly，cigarettes are very difficult to （48）D once a person has started smoking．Most teenagers start smoking （49）C they are influenced by friends or cigarettes advertisements．And often，the teenagers regret the decision to start smoking later in life．
Teenagers need to know （50）B bad cigarettes are for their health．If they are told that cigarettes kill more people than guns do，they probably will never start smoking．
Tobacco（烟叶） smoke has 43ingredients（成分） that may （42）C cancer．If smokers had learned these（43）A when they were young，they probably would never have started smoking．
Most smokers try （44）B first cigarette when they are teenagers．Often，they start smoking because they think that it makes them look more （45）D．Sometimes they start smoking because their friends tell them that it's cool．If teenagers are told that half of them will die before the age of 65from smoking cigarettes，how can they still think it's cool to smoke？
One of the biggest problems is cigarette advertisements．Tobacco companies （46）A tell the truth to teenagers（青少年） about cigarettes．After watching the advertisements on TV or looking at the posters in which people ride horses or play in a rock band，young people often think that smoking（47）C be cool．
Sadly，cigarettes are very difficult to （48）D once a person has started smoking．Most teenagers start smoking （49）C they are influenced by friends or cigarettes advertisements．And often，the teenagers regret the decision to start smoking later in life．
Teenagers need to know （50）B bad cigarettes are for their health．If they are told that cigarettes kill more people than guns do，they probably will never start smoking．
| 41．A．from | B．with | C．by | D．to |
| 42．A．produce | B．devote | C．cause | D．lead |
| 43．A．facts | B．information | C．message | D．news |
| 44．A．theirs | B．their | C．them | D．themselves |
| 45．A．out-going | B．hard-working | C．easy-going | D．grown-up |
| 46．A．never | B．often | C．sometimes | D．always |
| 47．A．need | B．might | C．must | D．may |
| 48．A．look up | B．put up | C．set up | D．give up |
| 49．A．so | B．although | C．because | D．but |
| 50．A．what | B．how | C．why | D．if |
8．While Jim ______the floor，someone ______at the door．（ ）
| A． | was sweeping，was knocking | B． | was sweeping，knocked | ||
| C． | swept，was knocking | D． | swept，knocked |
5．Mike's bike is red and _______ is blue．（ ）
| A． | my | B． | I | C． | her | D． | mine |