八年级英语下册 Unit 4 Look into Science Lesson 25Lesson 28重难点解析 冀教版.doc

unit 4 look into science一. 教学内容：unit 4 look into science lesson 25-lesson 281. 单词和短语n. science experiment theory jar upside force swimsuit observation conclusion mud liquid solid spoon cornstarch spoonful plate v. fill prove observe force examine discover explain add mix pour dissolve press taste empty adj. surprised enough weird empty full 2. 语法（1）一般将来时。（2）表达肯定与不肯定。3. 语言目标（1）well do the experiment and observe what will happen.（2）im sure/not sure.（3）there will be some showers this afternoon.（4）will you be free tomorrow?二. 重点、难点分析1. experiment是一个兼类词。n. 实验，试验；v. 做实验we often do experiments in our science class. 我们在自然科学课上经常做实验。 look! some boys are doing an experiment in the room. 瞧!几个男孩正在房间里做实验。can you experiment with the vcd player?你能试一下这台影碟机吗?2. fillwith用把（容器）装满，意同put sth. into sth. 把装 到（容器）里。 jack filled his backpack with books. jack put the books into his backpack. 杰克把书装进了书包。 fill in the blanks with the given words. 用所给的单词填空。 the girl is filled with joy（fear）. 这个女孩内心充满了喜悦（恐惧）。3. coverwith用把盖上，表示动作。 （1）cover n. 封面，盖子 v. 覆盖 david broke the cover of his book. 大卫把他的书皮撕破了。please cover the jar with a cover. 请用盖子把瓶子盖上。（2）be covered with被覆盖，覆盖着，表示状态。the ground is covered with snow. 地面被大雪覆盖了。4. a piece of cardboard一张纸板 piece用来表示不可数名词的量，块、件、条、片等。 a piece of music一段音乐 a piece of song一首歌 a piece of news一则消息 a piece of cloth一块布 在表示事物量的时候，piece可以根据实际情况用单数或复数，而名词则只能用单数。two pieces of chalk两枝粉笔five pieces of paper 5张纸please pass me a piece of paper. 请递给我一张纸。 tom was hungry，he ate two more pieces of bread. 汤姆饿了，他又吃了两片面包。5. upside down颠倒dont turn the box upside down. 不要把箱子弄颠倒了。the jar is upside down. 广口瓶倒放着。反义词：right side up正放，向上the jar is right side up. 广口瓶正放着。6. sure确定，确信，务必。下面总结一下其具体用法：（1）（美语）用于口语交际，当然，理应如此 are you going?你去吗? sure!当然去! can you give me your hand?你能帮我一下吗? sure!当然可以!（2）be sure of sth. 相信，确信某事 im sure of what he said. 我对他所说的确信无疑。 are you sure of it?你相信那件事吗?（3）be sure to do sth. 一定，务必。用于口语。 be sure to get to school on time. 一定按时到校。 be sure not to touch that machine. 一定不要动那台机器。（4）be surethat从句 he is sure that he can succeed. 他确信他能成功。（5）make sure从句，相信，确信 i make sure that he would go there. 我确信他会去那儿的。7. keep保管，保存，使保持，保守，饲养等。 how long may i keep the book?这本书我可以保存多久? keep the secret. dont tell anyone else. 请保守秘密。不要告诉别人。 uncle wang keeps a group of sheep. 王伯伯养了一群羊。（keep饲养） keep sth. （sb. ）形容词介词，让某人物保持某种状态。 please keep the room clean. 请保持室内清洁。 the cardboard can keep the water in. 纸板能把水控制在里面。 keep on doing sth. 继续或反复做某事（go on doing sth. ） the man was tired，but he kept on working. 那个人累了，但他仍坚持工作。8. wear穿着，戴着 ： mr. brown put on his hat and went out. 布朗先生戴上帽子出去了。 辨析：put on，puton，wear与dress put on穿上、戴上。强调动作过程。 puton意为“把挂（贴）在上。 wear穿着，戴着，强调结果。 dress up穿（衣服），打扮；n. 连衣裙。 its cold outside. youd better put on your thick clothes. 外面很冷。你最好穿上厚衣服。 please help me put the map on the wall. 请帮我把地图挂到墙上去。 miss zhao put a picture on the blackboard. 赵老师把一张图片贴在了黑板上。 maria often wears her red skirt. 玛丽亚经常穿着她的红裙子。the young man is wearing a pair of sunglasses. 那个年轻人戴着一副太阳镜。jenny is wearing a black and white dress. 詹妮穿着一件黑白相间的连衣裙。（dress n. 连衣裙）rose will go to a party. she is dressing herself. 罗斯要去参加一个聚会。她正在化妆。（dress up打扮，化妆）the little boy is too young to dress. 这个小男孩太小了，还不能自己穿衣服。（dress vt. 穿衣） 当dress用作“穿”“戴”时，后面不能加宾语（服装，鞋帽等）只能跟人作宾语而be dressed in可以跟衣服或表示颜色的词。如； today she is dressed in a red coat. 今天她穿着一件红色外套。9. 关于talk的短语 talk to sb. 一般介词to后跟表示人的名词或代词，意为“同谈话”。 mr. zhao is talking to brian. 赵老师正在同布莱恩谈话。 i have talked to him. 我已经跟他谈过了。 talk with sb. 与talk to sb. 意义接近，意为“和交谈”。注重其中的“交”，指谈话双方“相互”谈，不分主动、被动。 jenny is talking with her friends on her way home. 詹妮正在回家的路上和她的朋友交谈。 talk about sb. （sth. ）谈论的对象为人、物或事。 some children are talking about their new classmate. 几个孩子正在谈论他们班新来的同学。（谈论“人”） lets talk about our observations. 咱们把观察的结果讨论一下。（谈论“物”） next, we will talk about what he said. 下一步，我们讨论一下他的发言。（谈论“事”）10. putinto （1）把装（放）进（某容器） please put the waste paper into the basket. 请把废纸放进纸篓。 miss black put some rice into the bag. 布莱克小姐往袋子里装了些米。（2）把译成（记作）changeintotranslate（翻译） can you put the word into chinese?你能把这个单词译成汉语吗? please put the following sentences into english. 把下列句子译成英语。11. ask sb. to do sth. 要求某人做某事 句中的“某人”为宾语，后加动词不定式结构，作宾语补足语，其否定式为ask sb. not to do sth. 。 另有：want sb. to do sth. ，tell sb. to do sth. ，order sb. to do sth. 等。 mr. li asked us to observe what he did. 李老师要求我们观察他做的一切。 p1ease ask the boys not to speak loud in the room. 叫孩子们不要在房间里大声喧哗。12. bringto把带到 辨析：bring, take与fetch bring带来，指把某一物品从别处带到这里来，方向是“由彼及此”。 please bring me my book this afternoon. 今天下午请把我的书带来给我。 sorry，i forget to bring my homework. 对不起，我忘了带作业。 take带走，将物品从此处带往别处，方向是“由此及彼”。 dont forget to take the raincoat when you go to school. 上学的时候不要忘了带雨衣。 han mei took the desk to the next room. 韩梅把桌子搬到了隔壁房间。 fetch去拿来。指到某地去把物品带到这儿来。意同“go to bring”。 i have no chalk .please fetch me some. 我没有粉笔了。请去给我拿些来。 david fetched some paper for mr. liu. 大卫去给刘老师拿了些纸。13. 宾语从句 在一般情况下，一个名词、代词或动名词、动词不定式短语可以作宾语。 有时候由一个句子充当另一个句子中谓语动词的宾语，那么，作宾语的这个句子就叫做宾语从句。 jack told me that he would go back to his hometown next week. 杰克告诉我说他下周要回老家。 句中that为引导词，常常可省略。i dont know if there will be a match. 我不知道是否将有场比赛。（引导词if可以用whether替换） i asked him what his name was. 我问他叫什么名字。（句中what为引导词） that will prove who is right. 那将证明谁是正确的。（who is right为宾语从句）通过观察不难看出，无论原来的句子为何种句式（陈述句、一般疑问句或特殊疑问句），在充当宾语从句的时候，其语序一律为陈述语序。14. on top of在之上 he put his hand on top of his head. 他把手放在头上。 （1）on the top of在顶端；在顶部 there is a bird on the top of the house. 在屋顶上有只鸟。 （2）the top（物的）上面，上边，上部，上端the top of a shoe鞋面the top of a table桌面15. takeoff把从拿开，与take off（脱下）意义不同 dont take off your coat，its cold. 天很冷，不要脱掉外套。（take off把脱掉） bill took off his glasses. 比尔摘掉了眼镜。（take off摘掉） the plane will take off at 7：30 a.m. 飞机将在上午7：30起飞。（take off起飞） dont take your hand off the jar! 不要把手从瓶子上拿开!（takeoff把拿离）课本中另有一个句子：brian takes away his hand. （布莱恩拿开了他的手。take away拿开，但没有交待从哪里拿开，故不用“off”而用away，且将宾语（hand）放在后面。比较以下句子： who took away my book?谁拿走了我的书?（take away带走，拿走）16. surprise惊奇，to ones surprise使感到惊奇。surprised adj. 令人惊奇的，是动词surprise派生而来。英语中一个动词的过去分词有时可以作为形容词。这类构词法还有： break（被打破，损坏）-broken（破的，坏的） close（v. 关闭）-closed（关着的） amaze（n. 使惊讶）-amazed（令人惊讶的） interest（v. 使感兴趣）-interested（adj. 感兴趣的） be surprised at对感到奇怪，惊奇 to our surprise, jacks answers were all right. 使我们惊奇的是杰克的答案全对了。 mr. wang is surprised at lucys mind. 王老师对露西的想法感到惊奇。 after he did that，all of us were surprised. 等他做完那件事以后，我们都感到惊奇。17. examine vt. （1）考试 the students will be examined in english. 学生们将考英语。（2）检验；检查；审查；调查 examine a plan审查计划 the doctor examined her carefully. 医生给她做了仔细检查。18. strong enough足够有力enough是一个兼类词。现在来总结一下它的意义及用法： （1）enough a. “足够的”，一般作表语或修饰名词作定语。 it is enough for me to get one ticket. 对我来说，得到一张票就足够了。（enough作表语） dont worry，we have enough time. 不要担心，我们有足够的时间。（enough作定语） there are enough people to carry the big heavy box. 抬那个又大又重的箱子的人手足够了。（enough作定语） （2）enough adv. “足够地”，用来修饰形容词或副词。 the man is strong enough to carry the stone. 那个男子很壮，足以搬动那块石头。 i didnt run fast enough to keep up with tom. 我跑得不够快，跟不上汤姆。19. its time for lunch!现在是午饭时间!（该吃午饭了!）用于启发，提示别人。 its time for sth. 到了做的时间了。还可以表示为its time to do sth. 。 its time for school. its time to go to school. 该上学了。 its time for supper. its time to have supper. 该吃晚饭了。 20. taste （1）vt. 尝，品尝；辨（味），尝出味道。taste the apples尝苹果 can you taste anything strange in the soup?你尝出这汤里有什么怪味吗? （2）v. 有味道，后加表语，此时是连系动词。 it tastes sweet. 它吃起来很甜。 （3）n. 味道；滋味。sugar has a sweet taste. 糖有甜味。 have a taste of有的味道 it has a taste of apples. 这东西有苹果味。 英语中与感官有关的系动词：sound，look，smell，feel等。 the song the girl sang sounded wonderful. 那个女孩唱的歌听起来非常优美。 the old woman looks very worried. 那位老妇人看起来很着急。 i feel very tired（cold）today. 我今天感到很累（冷）。 the waste water smells very terrible. 那些废水难闻极了。 21. until prep. （1）prep. 用于肯定句中，意为“直到时，到为止”，后跟一个具体的时间点。 im going to stay here until saturday. 我要在这儿待到星期六。 （2）conj. 用于否定句中，即notuntil，意为“直到才”“不到不”，它表示主语的动作在某一时间或某一动作之前未发生。 dont go to bed until ten oclock. 不到10点不要睡觉。 i wont do that until you come back.