冊 1 · 基礎骨架 · Lesson 04
情態動詞：能力、義務、推測
Modals: Ability, Obligation, Deduction
情態動詞先選「力度」再選「禮貌」；C1 要會用推測語氣（must / might / can't）。
對比
| 較不自然／易錯 | 更自然的美式 | 說明 |
|---|---|---|
| You must to sign here. | You must / have to / need to sign here. | 情態後接原形 |
| You must come if free?（邀約） | You should come if you're free. / You might want to… | must 太硬，像命令 |
| He can be in a meeting.（推測） | He might / could be in a meeting. | can 少用於肯定推測 |
| You don't must go. | You don't have to go. / You mustn't go. | 不必 vs 禁止 完全不同 |
規則／用法
- 能力：can / be able to；過去能力 could / was able to（單一成功事件美式常用 managed to / was able to）。
- 義務：must（說話者強勢）、have to（外在規定）、need to（務實必要）、should / ought to（建議）。
- 禁止：mustn't / can't；不必：don't have to / don't need to。
- 推測強度：must（幾乎肯定）> should（合理期待）> might/could（可能）> can't（幾乎不可能）。
- 職場軟化：*You might want to…* / *We may need to…* 比 *You must…* 更 C1。
現代例句
- 房產
We may need to push the closing by a week.
我們可能要把成交延後一週。
- 投資
You might want to loop in your CPA before you promise that rent concession.
承諾租金讓利前，最好先找會計。
- 生活
He can't still be at the hardware store—it's been two hours.
他不可能還在五金行，都兩小時了。
- 房產
I should be done measuring rooms by five, assuming no surprises.
沒意外的話，我五點前能量完房間。
- 投資
Contractors have to carry insurance on every rehab site.
每個整修工地承包商都必須有保險。
- 生活
You don't have to bring a gift to the housewarming, but snacks are welcome.
暖房禮不必帶，但零食永遠受歡迎。
跟讀短文
約 82 words · TTS（瀏覽器語音）
We may need to push closing if the appraisal is late. You might want to loop in your lender today. Contractors have to carry insurance on site, and we shouldn't waive that requirement. I can't still believe the water heater is original—it must be near end of life. You don't have to buy furniture immediately after closing. You should, however, budget for a few urgent fixes. If the roof concerns you, we might get a specialist opinion before we finalize credits.
估價若延誤，我們可能要延後成交。你今天最好就把貸方拉進來。工地承包商必須有保險，這項不該放棄。熱水器居然是原裝的，我簡直不敢信——肯定快壽終了。成交後不必立刻買齊家具，但應該編一點緊急維修預算。若擔心屋頂，定案折讓前也許該找專人看。
慣用語包
might want to…
建議你…（軟）
職場
have to / need to
必須／需要
中性
shouldn't be an issue
照理不該有問題
職場
can't be right
這不可能對
口語／職場
迷你練習
- 分辨：You mustn't tell anyone. vs You don't have to tell anyone.
- 用推測：燈亮著但沒人應門 → 他們一定出去了／可能在院子。
- 把命令軟化：You must revise the deck today. → 職場版。