1、单元语法小专题(Grammar Focus)语法精讲一、祈使句祈使句常用来表示命令、指示、请求、要求或建议等。1当主语是第二人称 you 时，you 通常被省略。这种祈使句一般以动词原形开头。它的否定形式是在动词原形前加 dont。如：Be more careful next time.下次仔细点。Come to school earlier next time.下次早点来学校。Dont play computer games.不要玩电脑游戏。在祈使句的句首或句尾加 please，可以使祈使句的语气更委婉。但在句尾加 please 时，要在 please 前加逗号。如：Please speak
2、 loudly.Speak loudly，please.请大声讲话。2带有第一、第三人称主语的祈使句通常以 let为引导词，一般用来提建议。如：Lets watch the cartoon now.现在我们看卡通片吧。【拓展】lets/let me 祈使句的否定形式是 lets/let me not或 dont lets/let me；“let 第三人称”的否定形式为“dont let第三人称” 。如：Lets not play soccer in the street.我们不要在街上踢足球。Dont let her watch so much TV.不要让她看这么多电视。二、可数名词与不可数
3、名词普通名词分为可数名词和不可数名词。1可数名词可以用具体的数词来修饰，也可以用“数词计量名词of可数名词的复数形式 ”来表示。如：three apples 三个苹果；two bags of watermelons 两袋西瓜。2不可数名词没有复数形式，表示量时用“数词计量名词of不可数名词 ”结构。如：a cup of milk 一杯牛奶。3可数名词的量可以用 how many 提问；不可数名词的量可以用 how much 提问。4some，any， a lot of，lots of 等既可以修饰可数名词，又可以修饰不可数名词。语法精练.用括号内所给单词的适当形式填空。1Keep(keep)
4、quiet in the library.2Dont swim(swim) in the river ，please.3Please dont be(be) late for school next time.4You should not eat too much meat (meat)5They visited two big factories(factory) last month.6There is(be) some bread on the table.You can have some.7Would you like to buy some salt(salt)，Mrs.Smit
5、h?8Both his uncle and his aunt are famous scientists(scientist)9How much coffee(coffee) is there in the cup?10How many watermelons(watermelon) did you buy yesterday?.按要求完成下列句子，每空一词。11You must listen to the teacher carefully.(改为祈使句)Listen to the teacher carefully，please.12You cant pour the water into
6、 the pot.(改为祈使句)Dont pour the water into the pot.13I have two brothers.(对画线部分提问)How many brothers do you have?14There is a_little honey in the fridge.(对画线部分提问)How much honey is there in the fridge?15There is a tomato in the box.(用 three 代替 a 改写句子)There are three tomatoes in the box.根据汉语意思完成句子，每空一词。16请看第二幅图。Look at the second picture，please.17会议室里有几位工程师？How many engineers are there in the meeting room?18凯特，请不要打开搅拌机。Kate，please dont turn on the blender.19我们一起做香蕉奶昔吧。Lets make banana milk shakes together.20我想要一杯酸奶和两个汉堡包。I would like a/one cup of yogurt and two _hamburgers
