U4 · Grammar 预习笔记（背默版 · 20 条）
教材：译林版(2024) 8A U4《Hands-on fun》· Grammar（P44–45）
本课定位：U4 语法课，三大块打包——祈使句（发指令）+ should / had better（提建议）+ 否定前缀（构词法）。中考对"建议类"句型的考查几乎都落在这三条路上。
预测确定性：✅ 教材已确认 ｜ 条数：20 条
⏱ 20 分钟：保底 8 条 5′ → 句子精读 3′ → 进阶 6 条 4′ → 冲 A 6 条 3′ → 必背句 + 快测 5′；做不动就停在保底组。
一、核心词组 · 保底 8 条（中文 → 英文）
看中文说英文，说不出的看右侧英文，再遮住中文重来一遍。
| 笔记# | 中文 | 英文 | 红笔标注 / 考点 |
|---|---|---|---|
| 1 | 先读说明。 | Read the instructions first. | 祈使句：动词原形开头 |
| 2 | 不要用太多胶水。 | Don't use too much glue. | 否定祈使句：Don't + 原形 |
| 3 | 小心剪刀。 | Be careful with the scissors. | be 开头的祈使句 |
| 4 | 让我们一起做一朵纸玫瑰吧。 | Let's make a paper rose together. | Let's + 原形（邀请共同做） |
| 5 | 请把剪刀递给我。 | Pass me the scissors, please. | please 放句末使语气委婉 |
| 6 | 沿着线剪纸。 | Cut the paper along the line. | along 介词"沿着" |
| 7 | 把纸板对折。 | Fold the cardboard in half. | in half 对折 |
| 8 | 你应该先读说明。 | You should read the instructions first. | should + 原形（委婉建议） |
二、归类记忆 · 两条线
2.1 提建议三条路（语气由强到弱，作文按需要选）
| 路线 | 语气 | 结构 | 本课例句 |
|---|---|---|---|
| A. 祈使句 | 最直白（直接发指令） | 动词原形开头 / Don't + 原形 / Be + adj. | Read the instructions first. ｜ Don't use too much glue. ｜ Be careful with the scissors. |
| B. Let's | 邀请对方一起做 | Let's + 原形 | Let's make a paper rose together. |
| C. should | 委婉建议 | should + 原形 / shouldn't + 原形 | You should read the instructions first. ｜ You shouldn't touch the sharp tools. |
| D. had better | 语气最强（"最好……"） | had better + 原形 / had better not + 原形 | You'd better take an umbrella. ｜ You'd better not rush. |
2.2 否定前缀三条路（构词法）
| 前缀 | 规律 | 例词 |
|---|---|---|
| un- | 最常见 | lucky → unlucky ｜ usual → unusual ｜ happy → unhappy |
| in- | 另一常见 | correct → incorrect ｜ complete → incomplete |
| im- | 接 b / m / p 开头的词 | possible → impossible ｜ polite → impolite |
📖 三、句子精读（教材书例句 · 抓从句）
句子才是学英语的核心：先读出主干（谁 + 做什么），再找从句在修饰谁。每句读 3 遍。
| # | 教材书例句 | 中文 | 从句 / 考点拆解 |
|---|---|---|---|
| 1 | He should read the instructions before he starts the DIY job. | 他应该在开始 DIY 之前读一下说明。 | 时间状语从句：before 引导；情态动词 should + 动词原形；instruction 常用复数 |
| 2 | It's raining. You'd better take an umbrella. | 下雨了。你最好带把伞。 | had better do 最好做某事（后接原形）；'d better 是 had better 的缩写 |
| 3 | The teacher is coming! We'd better not talk. | 老师来了！我们最好别说话。 | had better not do（否定加在 better 之后）；现在进行时表即将发生 |
四、进阶 6 条
这 6 条重点看「红笔标注」，知道考什么比背下来更重要。
| 笔记# | 中文 | 英文 | 红笔标注 / 考点 |
|---|---|---|---|
| 9 | 你不应该碰锋利的工具。 | You shouldn't touch the sharp tools. | shouldn't = should not |
| 10 | 他应该在动手前读说明。 | He should read the instructions before DIY. | should 无人称和数的变化 |
| 11 | 你最好戴手套。 | You had better wear gloves. | had better + 原形（语气比 should 强） |
| 12 | 你最好不要着急。 | You had better not rush. | had better not + 原形 |
| 13 | 下雨了，你最好带把伞。 | It's raining. You'd better take an umbrella. | 'd better = had better |
| 14 | 老师来了！我们最好别说话。 | The teacher is coming! We'd better not talk. | had better not + 原形 |
五、冲 A 6 条
学有余力再攻。这几条串起了本课两大考点：建议句型 + 否定前缀。
| 笔记# | 中文 | 英文 | 红笔标注 / 考点 |
|---|---|---|---|
| 15 | 说明很重要→你应慢慢、仔细地读。 | Instructions are important. → You should read them slowly and carefully. | should + 原形；副词修饰动词 |
| 16 | 剪刀可能危险→你最好别玩它们。 | Scissors can be dangerous. → You'd better not play with them. | had better not + 原形 |
| 17 | 做……就／否则会…… | 祈使句 + and / or + 将来时句子 | 核心句式：and 表结果、or 表"否则" |
| 18 | 幸运的→不幸的 | lucky → unlucky | 否定前缀 un- |
| 19 | 正确的→不正确的 | correct → incorrect | 否定前缀 in- |
| 20 | 可能→不可能；礼貌→不礼貌；寻常→不寻常；完整→不完整 | possible → impossible ／ polite → impolite ／ usual → unusual ／ complete → incomplete | im- / un- / in- 三前缀 |
六、句型全家桶（本课句型对号入座）
| 句型 | 结构 | 例句 |
|---|---|---|
| 祈使句（肯定） | 动词原形开头 | Read the instructions first. |
| 祈使句（否定） | Don't + 原形 | Don't use too much glue. |
| 一起做某事 | Let's + 原形 | Let's make a paper rose together. |
| 应该做 | should + 原形 | You should read the instructions first. |
| 最好做 / 最好别做 | had better (not) + 原形 | You 'd better take an umbrella. ／ We 'd better not talk. |
| 祈使句 + and / or | 祈使句, and / or + 将来时 | Work hard, and you will pass. ／ Hurry up, or you will be late. |
七、易错提醒（只记正确写法）
- 祈使句用动词原形开头，主语 you 要省掉，动词不加 -s（Read…，不是 Reads…）
- 否定祈使句用 Don't + 原形（不用 doesn't / not）
- had better 后接原形：had better do（不是 to do）；否定是 had better not do——not 在 better 之后、动词之前
- should 无人称和数的变化：he should / they should 都一样，不加 s
- 否定前缀 im- 接 b / m / p 开头的词（possible、polite）；un-、in- 各有固定搭配
- instruction 表"用法说明"常用复数 instructions
八、同义句转换（中考句型转换的"等式"）
Read the instructions first.＝You should read the instructions first.You should read them first.＝You'd better read them first.Work hard, and you will pass.＝If you work hard, you will pass.Hurry up, or you will be late.＝If you don't hurry, you will be late.impossible＝not possible
📌 本课必背 3 句
- Read the instructions first, and be careful with the scissors.（先读说明，小心剪刀。）
- You should read the instructions slowly and carefully before DIY.（动手前你应慢慢、仔细地读说明。）
- It's raining. You'd better take an umbrella.（下雨了，你最好带把伞。）
🎤 学完就能用的一句话
You'd better read the instructions first.（你最好先读说明。）
🎯 快测 5 题（汉译英 · 答案就在上面）
把下面的中文翻成英文；不会的翻回去找，找到后读 2 遍（对 3 题就合格）：
- 先读说明。 2. 让我们一起做一朵纸玫瑰吧。 3. 把纸板对折。 4. 他应该在动手前读说明。 5. 下雨了，你最好带把伞。
答案：第 1、4、7、10、13 条
🔜 下一次预习：U4 · Integration
📖 预习用：本单元语法（祈使句 + should/had better）已核对，可放心提前学。