北师大版（2019）必修 第一册Unit 3 Celebrations同步练习卷（含解析）

北师大版（2019）必修第一册《Unit 3 Celebrations》同步练习卷（Topic Talk）
Ⅰ. 单句语法填空
1．He managed to remain cool by swimming 　 　（occasion）.
2．I am uncomfortable because my body is　 　 （stick）．
3．Birthday cakes are a 　 　 （tradition） part of birthday parties.
4．The 　 　 （decorate） on the wall are candles and a single mirror.
5．　 　 Christmas Day children can often get a lot of presents.
6．What do you want to do after 　 　 （graduate）？
7．The street was decorated with many 　 　 （lantern）.
8．　 　（congratulate） to you on winning the first prize in the English Speaking Competition.
9．The discussion finally came to 　 　 end.
10．　 　 （adult） need to live their own lives and that's difficult with children.
Ⅱ. 选词填空
11．on one occasion，graduate from，come to an end，be decorated with，at peace，congratulate...on...，stick to
（1）The great hall 　 　 beautiful flowers.
（2）　 　，she called me in the middle of the night.
（3）It is said that he 　 　 Peking University last year.
（4）After the exam，all the lessons in school also 　 　.
（5）The country has been 　 　 with its neighbour for two years.
（6）Unless they 　 　 their promise，we will stop working together with them.
（7）The problem was settled and his mind was 　 　.
（8）　 　，people play practical jokes on 1 April.
（9）She likes to 　 　 balls and to swim.
（10）I warmly 　 　 you 　 　 your successful performance.
Ⅲ. 完成句子
12．　 　 I have the time to spend a day with my kids.
我和孩子们度过一天的时候很少。（occasion）
13．There's plenty of rain in the southeast， 　 　.
东南部雨量充足，而西北部则很少下雨。（while）
14．　 　 to post this letter if you are busy.
如果你忙，让汤姆去邮局寄这封信。（let）
15．He became a college student 　 　.
他通过努力学习成了一名大学生。（by doing）
16．The Mid﹣Autumn Festival 　 　 on the 15th of the eighth lunar month.
阴历八月十五庆祝中秋节。（celebrate）
IV. 阅读理解
17．
Fantastic Fall Festivals You Won't Want to Miss
Seymour Apple Festival
Admission to the Seymour Apple Festival is free and so is the entertainment!More than 15，000 people from all over the region come out to take part in the activities，ranging from drawings，food，apple contests，and more.
Marionville Apple Festival
The popular Marionville Apple Festival is home to countless activities and events.The carnival，pony rides，and games will keep the kids busy
Humansville Fall Festival
The Humansville Fall Festival may be hosted by a small town，but that doesn't mean it's lacking big fun.Perfect for all ages，this fall festival is celebrating its 70th year and will provide three full days of fun.This year's festival will feature live music from fantastic local musicians，talented artisans selling their goods，and an amazing parade to wrap up the event on Saturday.
Southside Fall Festival
The Southside Fall Festival is perfect for family celebrations，with an alcohol﹣free environment and free admission.Enjoy a colorful parade and float contest，delicious food vendors，karaoke，and more.
Fall Into Arts Festival
Make sure to bring the kids along for this festival that celebrates all things creative.The Fall Into Arts Festival features a host of kid﹣friendly activities like a lego build，sand art，bubble stations，a jump house，and more.Parents will have plenty to do as well，festival food，a mini film festival
（1）Which festivals are free of charge？ 　 　
A.Southside Fall Festival and Fall Into Arts Festival.
B.Seymour Apple Festival and Southside Fall Festival.
C.Humansville Fall Festival and Fall Into Arts Festival.
D.Seymour Apple Festival and Marionville Apple Festival.
（2）What makes Humansville Fall Festival special this year？ 　 　
A.Fun activities on Saturday.
B.The duration of the festival.
C.The area of the hosting town.
D.Musicians' live performance.
（3）Who specially welcomes Fall Into Arts Festival？ 　 　
A.Movie lovers.
B.Modern artists.
C.Visitors of all ages.
D.Families with kids.
18．Around the world there are some festivals that for some of us may sound bizarre.
In England they celebrate the rolling cheese race，which occurs every year on the last Monday in May.This festival's characteristic is a contest where an official rolls cheese down a steep hill and festival﹣goers go chasing after it.The winner is the first one to reach and catch the cheese.
Another festival celebrated in England is the world championship of grimaces（鬼脸）.It is a celebration that dates back to 1297 and is celebrated during the month of September.The task is to perform the best grimace using anything you can to win.
The worldwide championship of wife lifting is celebrated in Finland.The game is based on Viking traditions where a man should carry away his neighbour's wife.According to the rules，any woman above 17 is considered as a wife，so if you are within this age：take care while visiting this country during the month of July.
Many of you have watched Pirates of the Caribbean and have known something about pirates.The 19th of September has been declared worldwide as the day to talk like a pirate.Plenty of people have celebrated it thanks to the publicity（宣传）on the Internet.
First staged in 1998，the Boryeong Mud Festival is an attraction that pulls more than a million visitors to the South Korean city.As you all know，the town is said to be rich in minerals
The Monkey Buffet Festival is held in Thailand to develop tourism.It's an annual feast held for about 600 monkeys.The Monkey Buffet Festival is held in honour of the Hindu gods Ram and Hanuman and involves 3，000 kilograms of vegetables and fruit being laid out for monkeys to stuff themselves.
（1）What does the underlined word "bizarre" in Paragraph 1 probably mean？ 　 　
A.Dangerous.
B.Strange.
C.Scary.
D.Familiar
（2）What should he or she do if a participant wants to win in the rolling cheese race？ 　 　
A.Roll as much cheese down the hill as possible.
B.Find the largest piece of cheese rolling downhill.
C.Perform the best grimace when chasing the cheese.
D.Be the first one to catch the cheese rolling downhill.
（3）According to the writer，when should a girl above 17 be careful？ 　 　
A.Enjoying the worldwide championship of wife lifting.
B.Enjoying the world championship of grimaces.
C.Enjoying the Boryeong Mud Festival.
D.Enjoying the Monkey Buffet Festival.
（4）Where should you go if you are interested in the Boryeong Mud Festival？ 　 　
A.England.
B.Finland.
C.South Korea.
D.Thailand.
V. 语法填空
19．Valentine's Day is known as a day of love and romance on February 14th every year．
There are a few different versions of its origin and history，one of which dates back （1）　 　 an ancient Roman festival，Lupercalia， （2）　 　 （celebrate） on February 15th．On this day，young single women would place （3）　 　 （they） names in a huge container and young bachelors of the town would come and draw a name from it．The young man and the woman， （4）　 　 name was picked would become partners for the （5）　 　 （follow） years．Many of these couples would eventually get（6）　 　（marry）．It （7）　 　 （believe） that the month of February is perfect for romance．
Valentine's Day was originally celebrated in Europe，but in recent years it is also celebrated in China，（8）　 　 （especial） among young people．Interestingly，China has its own Valentine's Day，on the 7th day of the 7th month of our lunar calendar．It is in memory of a day on which the legendary cow﹣herder and weaving﹣maid（9）　 　 （allow） to be together，after being separated by the Milky Way for a whole year．What （10）　 　 interesting story!
北师大版（2019）必修第一册《Unit 3 Celebrations》同步练习卷（Topic Talk）
参考答案与试题解析
Ⅰ. 单句语法填空
1．He managed to remain cool by swimming 　occasionally　（occasion）.
【分析】他偶尔游泳以保持冷静。
【解答】occasion"场合，时机 ； …的时候"，做状语修饰动词swimming。
故填：occasionally。
【点评】本题考查单词填空。首先根据句子结构和词与词之间的搭配关系判断应用所给词的何种词性进行填空，然后写出单词的适当形式。
2．I am uncomfortable because my body is　sticky　 （stick）．
【分析】我身上粘粘的，很不舒服．
【解答】sticky，考查形容词，充当表语．
【点评】对于单词填空这种题，要分析句子意思，再从结构上和意义上对答案进行确定．
3．Birthday cakes are a 　traditional　 （tradition） part of birthday parties.
【分析】生日蛋糕是生日派对的传统组成部分。
【解答】tradition"传统"。分析句子，设空处应用形容词traditional修饰part。
故填：traditional。
【点评】本题考查单词填空。首先根据句子结构和词与词之间的搭配关系判断应用所给词的何种词性进行填空，然后写出单词的适当形式。
4．The 　decorations　 （decorate） on the wall are candles and a single mirror.
【分析】墙上的装饰品是蜡烛和一面镜子。
【解答】decorate"装饰"，句中缺少主语，decoration是可数名词。
故填：decorations。
【点评】考查单词填空，准确地理解句子、翻译句子，然后根据句意及提示确定所填单词词性，对于动词要首先分辨是谓语还是非谓，若是谓语，则要注意时态语态和主谓一致；若是非谓则要考查主被动或是不定式；名词要注意单复数，正确写出单词完成句子，使句意更通顺。
5．　On　 Christmas Day children can often get a lot of presents.
【分析】在圣诞节，孩子们经常能得到很多礼物。
【解答】on Christmas Day在圣诞节那天，在特定的某一天要用介词on。
故填：On。
【点评】完成句子，要弄清楚各种句子即简单句，并列句和复合句的结构及连接词和句意，然后按要求完成句子。
6．What do you want to do after 　graduation　 （graduate）？
【分析】毕业后你想做什么？
【解答】分析句子，结合介词after，after graduation毕业之后。
故填：graduation。
【点评】本题考查单词填空。首先根据句子结构和词与词之间的搭配关系判断应用所给词的何种词性进行填空，然后写出单词的适当形式。
7．The street was decorated with many 　lanterns　 （lantern）.
【分析】这条街上挂着许多灯笼。
【解答】lantern（灯笼），是可数名词。
故填：lanterns。
【点评】考查单词填空，准确地理解句子、翻译句子，然后根据句意及提示确定所填单词词性，对于动词要首先分辨是谓语还是非谓，若是谓语，则要注意时态语态和主谓一致；若是非谓则要考查主被动或是不定式；名词要注意单复数，正确写出单词完成句子，使句意更通顺。
8．　Congratulations　（congratulate） to you on winning the first prize in the English Speaking Competition.
【分析】祝贺你在英语演讲比赛中获得一等奖。
【解答】congratulate"祝贺"，动词，应使用名词复数形式Congratulations。
故填：Congratulations。
【点评】本题考查单词填空。首先根据句子结构和词与词之间的搭配关系判断应用所给词的何种词性进行填空，然后写出单词的适当形式。
9．The discussion finally came to 　an　 end.
【分析】讨论终于结束了。
【解答】come to an end结束，是固定搭配。
故填：an。
【点评】完成句子，要弄清楚各种句子即简单句，并列句和复合句的结构及连接词和句意，然后按要求完成句子。
10．　Adults　 （adult） need to live their own lives and that's difficult with children.
【分析】成年人需要过自己的生活，这对孩子来说很难。
【解答】"adult"意为"成年人"，分析句子可知，横线处为主语，为原形形式，且adults位于句首。
故填：Adults。
【点评】本题考查单词填空。首先根据句子结构和词与词之间的搭配关系判断应用所给词的何种词性进行填空，然后写出单词的适当形式。
Ⅱ. 选词填空
11．on one occasion，graduate from，come to an end，be decorated with，at peace，congratulate...on...，stick to
（1）The great hall 　was decorated with　 beautiful flowers.
（2）　On one occasion　，she called me in the middle of the night.
（3）It is said that he 　graduated from　 Peking University last year.
（4）After the exam，all the lessons in school also 　came to an end　.
（5）The country has been 　at war　 with its neighbour for two years.
（6）Unless they 　stick to　 their promise，we will stop working together with them.
（7）The problem was settled and his mind was 　at peace　.
（8）　By tradition　，people play practical jokes on 1 April.
（9）She likes to 　play with　 balls and to swim.
（10）I warmly 　congratulate　 you 　on　 your successful performance.
【分析】（1）大厅里装饰着美丽的花朵。
（2）有一次，她在半夜给我打电话。
（3）据说他去年从北京大学毕业。
（4）考试结束后，学校的所有课程也都结束了。
（5）这个国家已与邻国交战两年了。
（6）除非他们信守诺言，否则我们将停止与他们合作。
（7）问题解决了，他心平气和。
（8）按照传统，人们在4月1日玩恶作剧。
（9）她喜欢玩球和游泳。
（10）我热烈祝贺你的成功表现。
【解答】（1）was decorated with.考查动词短语的时态。根据句意"大厅里装饰着美丽的花朵 decorated ，描述过去的事情，主语为单数名词。
（2）On one occasion.考查固定搭配。根据句意有一次。""可知要填的词为"on one occasion有一次"，所以开头字母要大写。
（3）graduated from.考查动词短语的时态。根据句意"据说他去年从北京大学毕业，根据时间状语last year，所以用一般过去时态。
（4）came to an end.考查动词短语的时态。根据句意"考试结束后。"可知要填的词为"came to an end结束"，所以用一般过去时态。
（5）at war.考查固定搭配。根据句意"这个国家已与邻国交战两年了，介词短语作表语。
（6）stick to.考查动词短语的时态。根据句意"除非他们信守诺言。"可知要填的词为"stick to坚持"，可知条件状语从句用一般现在时态。
（7）at peace.考查固定搭配。根据句意"问题解决了。"可知要填的词为"at peace心平气和"，故填at peace。
（8）By tradition.考查固定搭配。根据句意"按照传统。"可知要填的词为"by tradition按照传统"，所以开头字母要大写。
（9）play with.考查动词不定式。根据句意"她喜欢玩球和游泳，like to do sth.喜欢做某事，所以用动词原形。
（10）congratulate on.考查动词短语的时态。根据句意"我热烈祝贺你的成功表现，描述现状，故填congratulate on。
【点评】1.根据语法，判断词性
一般的空缺都可以通过其所在的句式结构和句法成分来判断其词性，从而正确的选词，进一步缩小词的选择范围。
2.利用语境，确定词形
当确定了一个单词的词性后，可通过上下文来帮助判断其形式，如主谓一致，动词的时态，语态，固定短语，名词的数和所有格，形容词，副词的比较级等。
Ⅲ. 完成句子
12．　Occasions are quite rare when　 I have the time to spend a day with my kids.
我和孩子们度过一天的时候很少。（occasion）
【分析】我和孩子们度过一天的时候很少。
【解答】因表示的是一般事实，要用一般现在时，用关系副词when引导从句，为分隔性定语从句。
故填：Occasions are quite rare when。
【点评】考查汉译英，注意英汉之间的差异，英语与汉语之间的一些特殊表达，准确地理解句子、翻译句子，然后根据句意及提示完成句子，使句意更通顺。
13．There's plenty of rain in the southeast， 　while there's little in the northwest.　.
东南部雨量充足，而西北部则很少下雨。（while）
【分析】东南部雨量充足，而西北部则很少下雨.
【解答】根据句意可知，横线处翻译为"而西北部则很少下雨"，主句有there is plenty of rain，"在西北部"译作in the northwest。全句综合即用while there's little in the northwest.
故填：while there's little in the northwest.
【点评】考查汉译英，注意英汉之间的差异，英语与汉语之间的一些特殊表达，准确地理解句子、翻译句子，然后根据句意及提示完成句子，使句意更通顺。
14．　Let Tom go to the post office　 to post this letter if you are busy.
如果你忙，让汤姆去邮局寄这封信。（let）
【分析】如果你忙，让汤姆去邮局寄这封信。
【解答】let sb.do sth.让某人做某事。根据句意，其英文是let Tom go to the post office。
故填：Let Tom go to the post office。
【点评】考查汉译英，注意英汉之间的差异，英语与汉语之间的一些特殊表达，准确地理解句子、翻译句子，然后根据句意及提示完成句子，使句意更通顺。
15．He became a college student 　by working hard　.
他通过努力学习成了一名大学生。（by doing）
【分析】他通过努力学习成了一名大学生。
【解答】根据句意，横线处应翻译"通过努力学习"。
故填：by working hard。
【点评】考查汉译英，注意英汉之间的差异，英语与汉语之间的一些特殊表达，准确地理解句子、翻译句子，然后根据句意及提示完成句子，使句意更通顺。
16．The Mid﹣Autumn Festival 　is celebrated　 on the 15th of the eighth lunar month.
阴历八月十五庆祝中秋节。（celebrate）
【分析】阴历八月十五庆祝中秋节。
【解答】The Mid﹣Autumn ，且表示一般事实；The Festival是单数概念。
故填：is celebrated。
【点评】考查汉译英，注意英汉之间的差异，英语与汉语之间的一些特殊表达，准确地理解句子、翻译句子，然后根据句意及提示完成句子，使句意更通顺。
IV. 阅读理解
17．
Fantastic Fall Festivals You Won't Want to Miss
Seymour Apple Festival
Admission to the Seymour Apple Festival is free and so is the entertainment!More than 15，000 people from all over the region come out to take part in the activities，ranging from drawings，food，apple contests，and more.
Marionville Apple Festival
The popular Marionville Apple Festival is home to countless activities and events.The carnival，pony rides，and games will keep the kids busy
Humansville Fall Festival
The Humansville Fall Festival may be hosted by a small town，but that doesn't mean it's lacking big fun.Perfect for all ages，this fall festival is celebrating its 70th year and will provide three full days of fun.This year's festival will feature live music from fantastic local musicians，talented artisans selling their goods，and an amazing parade to wrap up the event on Saturday.
Southside Fall Festival
The Southside Fall Festival is perfect for family celebrations，with an alcohol﹣free environment and free admission.Enjoy a colorful parade and float contest，delicious food vendors，karaoke，and more.
Fall Into Arts Festival
Make sure to bring the kids along for this festival that celebrates all things creative.The Fall Into Arts Festival features a host of kid﹣friendly activities like a lego build，sand art，bubble stations，a jump house，and more.Parents will have plenty to do as well，festival food，a mini film festival
（1）Which festivals are free of charge？ 　B　
A.Southside Fall Festival and Fall Into Arts Festival.
B.Seymour Apple Festival and Southside Fall Festival.
C.Humansville Fall Festival and Fall Into Arts Festival.
D.Seymour Apple Festival and Marionville Apple Festival.
（2）What makes Humansville Fall Festival special this year？ 　D　
A.Fun activities on Saturday.
B.The duration of the festival.
C.The area of the hosting town.
D.Musicians' live performance.
（3）Who specially welcomes Fall Into Arts Festival？ 　D　
A.Movie lovers.
B.Modern artists.
C.Visitors of all ages.
D.Families with kids.
【分析】本文是一篇广告布告类阅读，文章主要介绍了几个秋季的节日。
【解答】（1）B.细节理解题。根据Seymour Apple Festival介绍内容Admission to the Seymour Apple Festival is free and so is the entertainment，娱乐也是免费的，with an alcohol﹣free environment and free admission.南区秋季节非常适合家庭庆祝活动。可知，故选B。
（2）D.细节理解题。根据第三段This year's festival will feature live music from fantastic local musicians，这肯定会使它与往年的音乐节有所不同，今年的音乐节将以当地优秀音乐家的现场音乐为特色，故选D。
（3）D.推理判断题。根据最后一段Make sure to bring the kids along for this festival that celebrates all things creative.The Fall Into Arts Festival features a host of kid﹣friendly activities like a lego build，bubble stations，a jump house，with an excellent variety of artists，a mini film festival。秋季艺术节有许多适合儿童的活动、沙雕、用粉笔画人行道。父母也有很多事情要做、节日美食。可知，也有为父母准备的活动，故选D。
【点评】做这类题材阅读理解时要求考生对文章通读一遍，做题时结合原文和题目有针对性的找出相关语句进行仔细分析，结合选项选出正确答案。
18．Around the world there are some festivals that for some of us may sound bizarre.
In England they celebrate the rolling cheese race，which occurs every year on the last Monday in May.This festival's characteristic is a contest where an official rolls cheese down a steep hill and festival﹣goers go chasing after it.The winner is the first one to reach and catch the cheese.
Another festival celebrated in England is the world championship of grimaces（鬼脸）.It is a celebration that dates back to 1297 and is celebrated during the month of September.The task is to perform the best grimace using anything you can to win.
The worldwide championship of wife lifting is celebrated in Finland.The game is based on Viking traditions where a man should carry away his neighbour's wife.According to the rules，any woman above 17 is considered as a wife，so if you are within this age：take care while visiting this country during the month of July.
Many of you have watched Pirates of the Caribbean and have known something about pirates.The 19th of September has been declared worldwide as the day to talk like a pirate.Plenty of people have celebrated it thanks to the publicity（宣传）on the Internet.
First staged in 1998，the Boryeong Mud Festival is an attraction that pulls more than a million visitors to the South Korean city.As you all know，the town is said to be rich in minerals
The Monkey Buffet Festival is held in Thailand to develop tourism.It's an annual feast held for about 600 monkeys.The Monkey Buffet Festival is held in honour of the Hindu gods Ram and Hanuman and involves 3，000 kilograms of vegetables and fruit being laid out for monkeys to stuff themselves.
（1）What does the underlined word "bizarre" in Paragraph 1 probably mean？ 　B　
A.Dangerous.
B.Strange.
C.Scary.
D.Familiar
（2）What should he or she do if a participant wants to win in the rolling cheese race？ 　D　
A.Roll as much cheese down the hill as possible.
B.Find the largest piece of cheese rolling downhill.
C.Perform the best grimace when chasing the cheese.
D.Be the first one to catch the cheese rolling downhill.
（3）According to the writer，when should a girl above 17 be careful？ 　A　
A.Enjoying the worldwide championship of wife lifting.
B.Enjoying the world championship of grimaces.
C.Enjoying the Boryeong Mud Festival.
D.Enjoying the Monkey Buffet Festival.
（4）Where should you go if you are interested in the Boryeong Mud Festival？ 　C　
A.England.
B.Finland.
C.South Korea.
D.Thailand.
【分析】本文是一篇社会文化类阅读，作者通过这篇文章主要向我们介绍了世界上一些奇怪的比赛，主要讲了比赛内容以及其奇怪之处。
【解答】（1）B.词句猜测题。根据第二段In England they celebrate the rolling cheese race，人们在每年5月的最后一个星期一举行滚动奶酪比赛，官方将奶酪滚下陡峭的山坡。胜利者是第一个够到并抓住奶酪的人。这是一个庆祝活动可以追溯到1297年。这个任务就是尽你所能做出最好的鬼脸，这里介绍的节日有些奇怪。A.Dangerous.危险的；C.Scary.可怕的。故选B。
（2）D.细节理解题。根据第二段his festival's characteristic is a contest where an official rolls cheese down a steep hill and festival﹣ goers go chasing after it.The winner is the first one to reach and catch the cheese.他的节日的特色是一个比赛，参加节日的人去追逐它。可知，必须先把滚下山的芝士抓住。
（3）A.细节理解题。根据第四段According to the rules，so if you are within this age，任何超过17岁的女性都可以被视为妻子，在7月份访问这个国家时要小心，作者认为。故选A。
（4）C.细节理解题。根据倒数第二段First staged in 1998，是韩国吸引超过百万游客的景点，如果你对Boryeong泥巴节感兴趣。故选C。
【点评】做这类题材阅读理解时要求考生对文章通读一遍，做题时结合原文和题目有针对性的找出相关语句进行仔细分析，结合选项选出正确答案。
V. 语法填空
19．Valentine's Day is known as a day of love and romance on February 14th every year．
There are a few different versions of its origin and history，one of which dates back （1）　to　 an ancient Roman festival，Lupercalia， （2）　celebrated　 （celebrate） on February 15th．On this day，young single women would place （3）　their　 （they） names in a huge container and young bachelors of the town would come and draw a name from it．The young man and the woman， （4）　whose　 name was picked would become partners for the （5）　following　 （follow） years．Many of these couples would eventually get（6）　married　（marry）．It （7）　is believed　 （believe） that the month of February is perfect for romance．
Valentine's Day was originally celebrated in Europe，but in recent years it is also celebrated in China，（8）　especially　 （especial） among young people．Interestingly，China has its own Valentine's Day，on the 7th day of the 7th month of our lunar calendar．It is in memory of a day on which the legendary cow﹣herder and weaving﹣maid（9）　are allowed　 （allow） to be together，after being separated by the Milky Way for a whole year．What （10）　an　 interesting story!
【分析】文章讲述了情人节的起源，庆祝方式等．
【解答】1．to．"date to"意为"追溯到"．
2．celebrated．celebrate与festival构成动宾关系．故填celebrated．
3．their．此处用形容词性物主代词作定语修饰names．
4．whose．此处引导定语从句，并在从句中作定语．
5．following．此处是形容词作定语 adj．故填following．
4．married．get ．故填married．
7．is believed．句意：人们认为二月是浪漫的最佳季节．
8．especially．此处是副词作状语．故填especially．
8．are ．考查时态和语态 legendary and ，根据主句的谓语动词is可知．故填are allowed．
10．an．此处为what引导的感叹句!story为可数名词单数形式，故填an．
【点评】考查语法填空．语法填空主要考查用单词或短语的适当形式填空．做本题的关键是在理解短文的基础上，灵活运用所学的基础知识．本题考到的知识点有：固定的短语，词类的转换，名词的复数形式，副词以及祈使句的用法等．因此，这就需要在平时的学习中，牢固掌握各语言点及一些语法知识．