【用法】句中的which one to write是“疑问词 不定式”结构用在动词decide后作宾语。不定式可以与疑问词who, what, which, when, how, where 等连用，构成不定式短语，在句中作主语、表语、宾语和宾语补足语等。
【举例】①Where to buy this kind of computer is a problem. 到哪里去买这种计算机是一个问题。（作主语）②I really don’t know what to do. 我的确不知道该怎么办了。（作宾语）③The question is how to get there. 问题是怎么到那里去。（作表语）④Can you tell me which one to choose你能告诉我该选择哪一个吗（作宾语补足语） 2. If you think about it, it can take a long time to come up with the right words. 如果你考虑一下，找到合适的单词就要花费很长时间。
【用法】这句话中的if you think about it是条件状语从句，表示前提，短语think about意为“考虑”；
it can take a long time to come up with the right words是主句，其中的it是形式主语，动词take表示“花费”，真正的主语是后面的不定式to come up with the right words，短语come up with意为“想出”。
【举例】We don’t believe they can keep up with us. 我相信他们是不会赶上我们的。
3. I described something I love. 我描写了一些我喜欢的东西。
【用法】句中的I love是定语从句，用在不定代词something 之后作定语，前面省略了关系代词that。
【举例】She cooked something that we liked to eat. 她做了一些我们喜欢吃的东西。
Lesson 20 Say It in Five I. Learning aims Master the new words line, text, poet, single, screen, stretch, liquid, state, noun, adjective, verb, express II. Learning important and difficult points 1 Each line has a set number of words. 2）Let’s look at another two poems as examples. 3）Describe your topic in two words. 4 Choose three words that describe what your topic does. Language Points 2 1. Each line has a set number of words. 每行有固定数目的单词。
【用法】a number of的意为 “一些”，与some或several同义，后面往往加名词复数。以a number of短语作主语时，谓语动词往往用复数形式。句中的set是过去分词起形容词作用，意为“固定的、规定的”，修饰后面的名词number。
【举例】①There are a set number of workers in each workshop. 每个车间都有固定数量的工人。②A number of tourists have come back already. 一些游客已经回来了。
【拓展】the number of的意为“的数目”，后加名词复数。以the number of短语作主语时，谓语动词往往使用单数形式。
2. Describe your topic in two words. 用两个单词描写你的主题。
【用法】介词in 在这里表示方式，后加名词、代词、动名词，多用在动词后作状语。
【举例】Can you say these words in another way 你能用另一种方法说出这些单词吗 Lesson 21 The Fable of the Woodcutter I. Learning aims Master the new words fable, woodcutter, axe, spirit, dive, admit, fetch, silver, policy II. Learning important and difficult points 1 She listened to the woodcutter and felt sorry for him. 2 The man looked at the gold axe, knowing it wasn’t his. 3 The spirit went down a third time and returned with the woodcutter’s old axe. 4 The spirit was so happy with the woodcutter’s honesty that she gave him the other two axes as presents. Language Points 1. spirit 【用法】作可数名词，意为“精灵”，复数形式是spirits。
【举例】They all call her the little spirit. 他们都把她叫做小精灵。
【用法】作不可数名词，意为“精神”。
【举例】We should learn this spirit in our work. 我们应该在工作中学习这种精神。
2. She listened to the woodcutter and felt sorry for him. 她听了伐木人的话，对他感到很抱歉。
【用法】句式feel sorry for意为“对感到抱歉、遗憾、后悔”，后加名词、代词、动名词作介词for的宾语。
【举例】①She felt really sorry for that matter. 她对那件事情感到很后悔。②We felt sorry for what we had done. 我们对我们所做的事情感到抱歉。
3. The man looked at the gold axe, knowing it wasn’t his. 那个人看了看这把金斧子，他知道这不是他的。
【用法】句中的knowing it wasn’t his是现在分词短语作状语，表示伴随状况。
【举例】Mr. Zhang walked into the classroom, holding two books in his hand. 张先生手里拿着两本书走进了教室。
Lesson 22 The Giant I 3 I. Learning aims Master the new words giant, loud, frightened, lie, awake, musician II. Learning important and difficult points 1 Its trees were filled with singing birds. 2 One day as the children were playing, a giant appeared. 3 The green grass was covered with snow. 4 He thought it must be the king’s musicians passing by. Language Points 1. lie 【用法】作不及物动词，意为“躺、平放、位于、撒谎”，注意，作“撒谎”讲时，过去式、过去分词是lied, lied，作其他含义讲时，过去式、过去分词是lay, lain；
它的现在分词都是lying。
【举例】①Shanghai lies in the east of China. 上海位于中国东部。②She lied to us again. Did you think so 她对我们又撒谎了。你这样认为吗 【用法】作可数名词，意为“谎言”，短语tell a lie意为“撒谎”。
【举例】Why did he tell lies this time 这一次他为什么要撒谎 2. Its trees were filled with singing birds. 树上都是鸟儿在歌唱。
【用法】句中的be filled with 意为“充满”，其中的filled 是动词fill的过去分词起形容词作用，用在系词be后作表语，介词with 加上名词或代词后作状语。在意义上与be full of 同义。
【举例】The basket is filled with fresh flowers. 篮子里装满了鲜花。
3. He thought it must be the king’s musicians passing by. 他想这一定是国王的乐师在这里经过。
【用法】情态动词must 加上动词原形表示肯定推测的含义。
【举例】He wasn’t in the classroom. He must play on the playground. 他没在教室里。他一定在操场上玩呢。
【拓展】情态动词can’t加上动词原形表示否定推测的含义。
【举例】She can’t be in Washington because I saw her here just now. 她不可能去华盛顿了，因为刚才我在这里还见到了她。
Lesson 23 The Giant II I. Learning aims Master the new words softly, scene, selfish, knock, spread, neck, wicked giant, loud, frightened, lie, awake, musician II. Learning import