这个单元有 5 章：原创课文「看不见的代价」、词汇延展（环境/生态词族与习语）、语法延展（倒装：Not only.../Little do we.../Under no circumstances...）、功能句型（Writing Essay 环境话题 + 口语 Part 3 协作）、CPE 考点与 8 题自测。
学完你能：用倒装句强调环境问题的紧迫性，写出 Not only does... / Under no circumstances should we...；区分 emission/pollution 的语域。
预计时间：约 1 周半。
衔接说明：你在 Unit 1 已会 Rarely do we 类前置，本单元扩展到全部否定副词与 only 的倒装。
环境单元 = 生态词族 + 倒装。课文写 narrator 考察一条河流的变化，词汇按「污染/缓解/后果」分组，语法攻克否定状语前置的全套倒装。
主题课文 · 那条曾经清澈的河
课文 · Tip of the Iceberg
（可参看本单元语法深化页）课文精讲 · C2 怎么把观点说透
论为什么这段课文是「倒装强调教材」
普通写法：A river has rarely changed so fast. The kingfishers are gone. The water has grown polluted, and the food chain is disrupted.
C2 写法（否定倒装）：Rarely has a single river changed so dramatically... Not only has the water grown polluted, but the food chain has been disrupted. Under no circumstances should this continue. No sooner had the factory opened than the fish died.
升级点 1 — 否定副词前置倒装：Rarely has... / Little do those... 把助动词提前。
升级点 2 — Not only 倒装 + but：Not only has the water..., but (also) the food chain... 前倒后不倒。
升级点 3 — No sooner...than：No sooner had X happened than Y followed（一…就…）。
① tip of the iceberg 冰山一角
② reap what you sow 自食其果
③ in the long run 从长远看
④ beyond recovery 无法挽回
⑤ on every level 从各方面
词汇延展 · 环境与生态词族
环境生态词族（C2 高频）
| 组 | 核心词 / 搭配 / 习语 | 备注 |
|---|---|---|
| 污染与枯竭 | emission, depletion, contamination, deforestation, depletion, smog, toxic | carbon emission 碳排放 |
| 缓解与行动 | mitigate, conserve, sustainable, renewable, offset, curb, phase out | phase out 逐步淘汰 |
| 后果 | catastrophic, repercussion, irreversible, drought, extinction, degradation | irreversible 不可逆的 |
| 正式习语 | tip of the iceberg, reap what you sow, in the long run, leave a footprint | Essay 必备 |
| 词族转换 | emit→emission; deplete→depletion; degrade→degradation; sustain→sustainable | Part 3 直接考 |
① emission vs pollution：emission = 排放（气体）；pollution = 污染（总称）。carbon emissions。
② affect vs effect：affect 动词；effect 名词。the effects of pollution。
③ irreversible ≢ irreverent：irreversible 不可逆；irreverent 不恭敬。
④ renewable 注意拼写：不是 renwable。
语法延展 · 否定状语前置倒装
否定倒装全表
| 结构 | 含义/用法 | 例句 |
|---|---|---|
| Rarely/Seldom/Never + 助动词+主语 | 否定频度副词前置 | Rarely has a river changed so fast. |
| Under no circumstances + 倒装 | 「绝不」 | Under no circumstances should we delay. |
| Not only + 倒装, but (also) | 「不仅…而且」 | Not only has it polluted water, but it has ruined soil. |
| No sooner had + 主语 + 过去分词 + than | 「一…就…」 | No sooner had it opened than fish died. |
| Hardly/Scarcely had... when | 「刚…就…」 | Hardly had we arrived when it rained. |
| Only + 状语 + 倒装 | Only then / Only by... | Only by acting now can we avert disaster. |
① 否定副词前置必须倒装：❌ Under no circumstances we should. → ✅ Under no circumstances should we.
② Not only 倒装，but also 不倒装：Not only has it..., but it has also...
③ No sooner 配 than，Hardly 配 when：别用错连词。
考试怎么考：Part 4：We must not delay under any circumstances. → Under no circumstances must we delay.
情景操练
即学即用
练习1（倒装）：① We have rarely seen such destruction. → Rarely ___ ___ such destruction. ② We must not ignore this. → Under no circumstances ___ ___ ignore this.
练习2（Not only）：The factory pollutes the river. It also wastes energy. → Not only ___ the factory ___ the river, but it also wastes energy.
练习3（No sooner）：The dam was built. The floods began immediately. → No sooner ___ the dam ___ than the floods began.
练习4（写自己的话）：用 Only by...can we... 写一句关于环保的 Essay 句。
查看参考答案
- 练习1：① Rarely have we seen ② Under no circumstances must we
- 练习2：Not only does the factory pollute the river（一般现在时用 does）
- 练习3：No sooner had the dam been built than...
- 练习4（示范）：Only by cutting emissions decisively can we avert the worst consequences.
功能句型 · Essay 环境话题 + 口语 Part 3 协作
三套句型模板
Never has the need for action been more pressing.
Only by confronting these issues head-on can we hope to...
It is, unfortunately, only the tip of the iceberg.
A concerted effort is required to curb...
Rather than merely treating the symptoms, we must address the root cause.
Governments, industry and individuals alike all have a part to play.
Shall we tackle the most urgent issue first?
I take your point, but might it be wiser to...?
How do we weigh long-term gain against short-term cost?
场景对话 · 口语 Part 3 讨论「城市该如何应对环境问题」
Student A: Right. Under no circumstances can we afford to do nothing. Not only does air pollution harm health, but it also drags on the economy. Shall we tackle public transport first?
Student B: I take your point, yet only by tackling waste at source can lasting change occur. How do we weigh long-term gain against short-term cost?
Student A: Fair enough. Rarely do cheap measures work, so investment is unavoidable. No sooner had we invested in cycling lanes than emissions began to fall, or so the data suggests.
Student B: Then let's agree on cleaner transport and waste reduction as our top two.
Student A: Done. Prevention, after all, beats cure.
CPE 考点 · 环境危机主题怎么考 + 自测
考点分布表
| 卷子/部分 | 题型示例 | 应对策略 |
|---|---|---|
| Reading & Use Part 4 | KWT：Under no circumstances / Not only... / No sooner | 2 词改写 |
| Reading & Use Part 3 | 词形：emit→emission, deplete→depletion | 判断词性 |
| Reading Part 6 | 跨文本配对：两篇文章对核能/环保的态度 | 抓立场语气 |
| Writing Part 1 | Essay：环保责任在个人还是政府 | 否定倒装开头 + 对策 |
| Speaking Part 3 | 协作选最有效环保措施 | weigh...against... + 倒装 |
本单元自测 · 8 题
环境危机自测
1（倒装）：We have seldom seen such damage. → Seldom ___ ___ such damage.
2（倒装）：We must not ignore the warning. → Under no circumstances ___ ___ ignore the warning.
3（词形）：Carbon ___ are rising. (emit)
4（Not only）：Not only ___ the river ___, but the soil was poisoned. (pollute)
5（No sooner）：No sooner ___ the dam ___ (build) than floods came.
6（易混）：The ___ of the rainforest is alarming. (depletion / pollute)
7（写作）：用 Only by...can we... 写一句环境 Essay。
8（口语）：用 tip of the iceberg 说一句关于污染的话。
查看参考答案
- 1：Seldom have we seen
- 2：Under no circumstances must we
- 3：emissions（复数）
- 4：Not only was the river polluted
- 5：No sooner had the dam been built
- 6：depletion（雨林枯竭）
- 7（示范）：Only by altering our consumption habits can we hope to reverse the trend.
- 8（示范）：What we see here is, experts warn, merely the tip of the iceberg.
论从倒装到考场节奏
本单元你拿下的：Rarely/Seldom/Under no circumstances/Not only/No sooner/Hardly/Only 倒装。
写作提示：一篇 Essay 用一个倒装开头点睛即可，别三句都倒装。
现在就做：把课文四个倒装句遮住中文重写。
在线学习资源 · 剑桥官方
本课程课文与练习均为同主题原创仿真题，知识点对齐 C2 官方大纲，不复制真题原文。