1、第八单元语法单词语法祈使句用来表示请求、命令、叮嘱、邀请、劝告或祝愿等，因此祈使句中一般没有主语，但根据其句意，实际上是省略了主语you，直接用动词原形开头，句尾用句号或感叹号。有时，在祈使句前面或末尾加上please，显得有礼貌。 肯定的表达1.以动词原形开头例：Have a nice weekend!祝你周末愉快！Be careful!小心！Come in, please!=Please come in!请进！2.以Let开头例：Let me help you!让我来帮你！Let us try again!让我们再试一次！Lets sing together!我们一起唱歌吧！ 祈使句否定的
2、表达1.Dont动词原形其他成分.例：Dont say that again!别再那样说了！2.Dontbe其他成分（形容词、名词或介词短语等）.例：Dont be careless.不要粗心。3.let引起的祈使句的否定形式有两种：let开头的祈使句，如果后面跟第一、第三人称名词或代词的宾格，可在let前加Dont，也可在let后的宾语后面加not；如果以Lets开头的祈使句，必须在Lets后加not。例：Dont let me go with her tomorrow. = Let me not go with her tomorrow.不要让我明天跟她一起去。Lets not tell
3、her the true story.我们别把真相告诉她。4.常用No doing! No +n.句型表达在某些场合“禁止某种行为”，或对某种行为进行劝阻，但并非所有的动词或名词都可以这样表达，常见的搭配如下：祈使句的反意疑问句省去主语的祈使句的反意疑问句，疑问部分通常用willyou。例：Dontdothatagain,willyou?Gowithme,willyou/wontyou?陈述部分形式为Lets，疑问部分用shallwe，而陈述部分形式为Letus，疑问部分用willyou。例：Letstryharder,shallwe?Letusgonow,willyou?总结-She nee
4、ds three large loaves of bread.她需要三大条面包。How many、How much 一、对数量进行提问how many后接可数名词复数。例如：How many flowers are there in the vase? 花瓶里有多少支花儿？how much后接不可数名词。例如：How much water is there in the bottle? 瓶子里有多少水？二、对价格、重量、数字运算结果以及程度进行提问how much意为“多少”。询问重量，例如：-How much does the pig weigh? -Eighty kilos.-这头猪多重？
5、-八十公斤。how much意为“多少”。询问价钱How much is your new computer? 你的新电脑多少钱？how much意为“多少”。询问运算结果-How much is 3 plus 3？-Six.-三加三是多少？-六。不可数名词的用法和计量名词是表示人、事物和抽象概念的词。它有可数名词和不可数名词之分。可数名词有单复数之分。如:abag，twobags。而不可数名词，顾名思义，通常没有复数形式，不能在词尾加s或es变复数。常见的不可数名词有:ice,rain,snow,sun,wind,bread,meat,juice,sugar等。还有像work(工作),hel
6、p(帮助),love(爱),hope(希望),weather(天气)等抽象名词也是不可数名词。在使用不可数名词时,要注意以下几点:1.不可数名词前面不能直接加a/an。I like to skate on an ice.()I like to skate on the ice.()我喜欢在冰上滑冰。2.不可数名词如果要表示一定的数量，需要借助单位词。如:a bar of chocolate一块巧克力 a glass of water 一杯水a cup of coffee一杯咖啡 three bowls of rice 三碗米饭two pieces of paper两张纸 five pieces
7、 of bread 五片面包3.some，any，a little，a lot of，lots of，an amount of等可以加在不可数名词的前面，修饰不可数名词。I need some help.我需要一些帮助。He drinks three glasses of water and still feels thirsty.他喝了三杯水，还是觉得口渴。James had two bowls of rice and some fish for lunch.James午饭吃了两碗米饭和一些鱼。不可数名词和可数名词比较 顺序关系的副词常用的表特定的顺序关系的副词有：首先：first、firs
8、tly.其次：second、secondly.接着：then、next.最后：finally、lastly.例：Firstly, its expensive, and secondly, its too slow.首先是价格贵，其次，速度太慢。Next, I heard the sound of voices.接着，我听到了说话的声音。序数词+ly，常可用作表特定的顺序关系的副词，表示“第几”。如：thirdly第三。单词turn on/off/down/upturn on意为“（把水源、煤气、电源等）打开”，其反义词组为turn off“关上”。turn down意为“（把收音机的音量、灯的
9、亮度等）关小、调低”，也有“拒绝”之意。turn up“（把收音机的音量、灯的亮度等）调高”，此外turn up也有“出现”之意。这些短语中，on，off，up和down均为副词，后接代词时，代词应位于副词的前面。Please turn off/on the radio.请把收音机关上/打开。The music is very loud. Can you turn it down a little, please?音乐声音太大。你能关小一点吗？She sat down and turned up the heat.她坐下来，把温度调高。mix/mix up/mixture1.mixv.（使）混
10、合；拌和；（使）结合mix(sth.) with sth.把与混合、拌和Shake the bottle well to make the oil mix with the vinegar.充分摇动瓶子使油和醋混合。mix sth.togetherMix all the ingredients together in a bowl.把所有的配料放在碗里，搅和一下。mix (sb./sth.) up搅拌；混淆，弄混；弄乱Someone has mixed up all the application forms.有人把申请表都弄乱了。I always mix him up with his br
11、other. They look so much alike.我总是把他和他弟弟弄混，他们长得太像了。2.mixn.混合；混合配料（同mixture）Add water to the cake mix and bake at 375F.往蛋糕粉里加水，然后在375华氏度的温度下烘烤。3.mixturen.混合；混合体；混合料The town is a mixture of the old and the new.这个小城新旧结合。Pour the mixture into four small dishes.把混合料倒入四个小碟子里。fillfillvt./vi.（使）充满；装满1.vt.使充
12、满，装满，盛满，注满Clive filled his pockets with apples. Clive给口袋里装满了苹果。 Iwas filled with gratitudefor her.我对她充满了感激之情。2.vi.满，充满The theatre soon filled with people.剧院里很快就挤满了人。The hall filled quickly.大厅很快就挤满了人。 3. be filled with=be full of“装满；充满”The air was filled with the sound of childrens laughter.空气中荡漾着孩子们
13、的笑声。serve/service/servantservev.招待，供应；为服务；服役；对有用，能起作用The waiter was serving another table.那名侍者正在接待另一桌客人。Meals can be served to you in your room.饭菜可以送到你的房间里。serve as.当作，担任，充当This room serves as her office.这个房间用作她的办公室。servicen.服务，服侍；服役Our aim is to provide the best service at the lowest price.我们的目标是以最
14、低的价格提供最好的服务。bein service在使用中；可供使用These trains have been in service for many years.这些火车已经使用很多年了。beout of service不在使用中；不能使用servantn.仆人；雇员；公务员He is a trustedservant ofthecompany.他是公司一名可靠的雇员。covercovern./v.1.covern.覆盖物，遮盖物；封面，封底；被子；躲避处Her face was on the front cover of various kinds of magazines.各种杂志的封面
15、都有她的头像。Everyone ran for cover when it started to rain.雨下起来时，大家都跑着找地方避雨。2.coverv.遮盖；覆盖；包括；走完（一段路程）；占地；足以支付The desk was covered with papers.书桌上铺了些报纸。Much of the country is covered with snow.这个国家的大部分地区都被白雪覆盖。They were hoping to cover 40 miles yesterday.他们昨天是打算走40英里的。The city covers 25 square miles.这个城市占地25平方英里。The show barely covered its costs.这场演出勉强够本。cover. with.用覆盖=be covered with.cover sth. up遮盖某物；掩盖某事cover (sb.) up意为穿上衣服；盖上毯子