9.2 Use of Chinese: Logical Errors and Ambiguity (句子辨析：邏輯錯誤與歧義)
Key Takeaways
In the CSB sample, 「只有水量合適，農作物才能豐收。今年農作物沒有豐收，所以今年水量不合適」 is a logical error, because 只有……才…… sets a necessary condition and a failed harvest can have other causes.
Listing overlapping categories, as in 服務對象是男性和中下階層, mixes two classification standards (分類標準不一) and is a logical error.
A sentence that calls ten predictions 完全準確 and then admits one 有點差誤 contradicts itself (自相矛盾).
Stacked negatives such as 防止……不再 or 難免不 can reverse the intended meaning, so count every negative word before accepting a sentence.
Structural ambiguity (歧義), as in 三個部門的主管, arises when a phrase can be grouped in two ways.
9.2 Use of Chinese: Logical Errors and Ambiguity (句子辨析：邏輯錯誤與歧義)
Quick Answer: Some 句子辨析 items ask you to find the sentence that does or does not contain a logical error (邏輯錯誤). A logically faulty sentence can be grammatically perfect. Check for faulty conditional reasoning (only 只有……才……, 只要……就……), overlapping categories in a list, self-contradiction, too many negatives, illogical judgements and ambiguity.
The official sample, explained
選出沒有犯邏輯錯誤的句子。 A 只有水量合適，農作物才能豐收。今年農作物沒有豐收，所以今年水量不合適。 B 在世界教育史上，中國是很早出現學校的一個國家。 C 這間公司的服務對象是男性和中下階層。 D 他的十個預測完全準確，只是最後一個有點差誤。 答案：B
| Sentence | Fault | Explanation |
|---|---|---|
| A | Faulty conditional reasoning | 只有 P 才 Q makes P necessary for Q: a good harvest requires suitable water. A poor harvest does not prove the water was unsuitable, because pests or weather could be the cause |
| B | None | The sentence says China was one of the countries where schools appeared very early. It makes a careful claim, not an absolute "first" |
| C | Overlapping categories | 男性 (sex) and 中下階層 (social class) are classified by different standards and overlap. Men from the lower and middle classes belong to both groups |
| D | Self-contradiction | 完全準確 (completely accurate) cannot coexist with 最後一個有點差誤 (the last one slightly off) |
Type 1: faulty conditional reasoning
Chinese conditional connectives carry exact logical meanings (see also Section 5.2):
| Connective | Logical meaning | Valid inference | Invalid inference |
|---|---|---|---|
| 只要 P，就 Q | P is sufficient for Q | P happened, so Q happens | Q happened, so P happened |
| 只有 P，才 Q | P is necessary for Q | P did not happen, so Q does not happen | P happened, so Q happens; or Q did not happen, so P did not happen |
| 除非 P，否則不 Q | Same as 只有 P 才 Q | Without P, no Q | With P, therefore Q |
The official sample's sentence A reasons from "no harvest" to "no suitable water". That runs the necessary condition the wrong way. A second common fault is mixing the pairs, such as 只有……就…… or 只要……才……. These are both grammatical mismatches and logical errors.
Type 2: overlapping categories (並列不當)
Items joined by 和, 及, 與 or listed with 、 must be parallel and non-overlapping:
- Different standards: 男性和中下階層 (sex and class).
- Whole and part listed together: 本港居民和新界居民. 新界居民 are already 本港居民.
- Category and member listed together: 蔬菜和白菜. 白菜 is a kind of 蔬菜.
The fix is to use one standard (男性和女性) or to restructure (本港居民，特別是新界居民).
Type 3: self-contradiction (自相矛盾)
Watch for absolute words followed by exceptions, and for numbers that cannot all be true:
- 全部 or 完全 followed by 只是……有誤 or 部分.
- 出席率接近百分之一百二十: an attendance rate cannot exceed 100 per cent.
- 唯一……之一: 唯一 means the only one, so it cannot be combined with 之一 (one of several). By contrast, 最……之一 (one of the most) is acceptable.
- 大約……整整: an approximate and an exact quantity in the same phrase.
Type 4: too many negatives (否定失當)
Count every negative word, including those built into verbs such as 防止, 避免, 禁止, 杜絕 and 否認:
| Faulty sentence | Problem | Correction |
|---|---|---|
| 為了防止私隱資料不再外洩…… | 防止 plus 不再 reverses the meaning | 防止私隱資料外洩 |
| 我們不能否認這不是一個好機會。 | Three negatives amount to one, which reverses the intended meaning | 我們不能否認這是一個好機會 |
| 新同事難免不犯錯，大家應多包容。 | 難免 already means "can hardly avoid"; adding 不 says new colleagues will not make mistakes | 新同事難免犯錯 |
Type 5: illogical judgements (判斷不當)
A "是" sentence must equate things of the same kind:
- 香港的氣候是一個溫暖潮濕的地方。 Climate is not a place, so the fix is 香港的氣候溫暖潮濕.
- 本署的宗旨是一個以民為本的部門。 A mission (宗旨) is not a department, so the fix is 本署的宗旨是以民為本.
Type 6: ambiguity (歧義)
A sentence is ambiguous if it can be read in two ways:
| Ambiguous sentence | Two readings | Clear version |
|---|---|---|
| 三個部門的主管出席了會議。 | Three managers, or the managers of three departments | 三名部門主管 or 來自三個部門的主管 |
| 他和秘書的上司開會。 | He met (the secretary's boss), or (his and the secretary's) boss held a meeting | 他跟秘書的上司開會 |
| 他走了一個多小時。 | He walked for over an hour, or he left over an hour ago | 他步行了一個多小時 / 他已離開了一個多小時 |
A checklist for logic items
- Find the claim words: 只有, 只要, 除非, 一定, 全部, 唯一, 之一 and numbers.
- Test conditionals with the table in Type 1.
- Check lists for overlapping or unequal categories.
- Count the negatives and work out the overall meaning.
- Check "是" sentences: are both sides the same kind of thing?
- Try a second reading of any noun phrase with a number or 和.
Combining logic and structure checks
On the paper you will not be told whether an item tests structure or logic. The stem simply says 選出有語病的句子 or 選出沒有犯邏輯錯誤的句子. Run the structural checks from Section 9.1 first, because they are quicker. If every sentence is structurally sound, switch to the logic checks above. In the official logic sample, every sentence is grammatical, so only the logic checklist separates them. Practise by writing your own sentence for each of the six types; producing an error is the surest way to recognise it under time pressure.
下列哪一句沒有犯邏輯錯誤？
這間公司的員工包括經理、文職人員和女性員工。
這次簡介會的出席率接近百分之一百二十。
香港是亞洲重要的金融中心之一。
他的報告內容全部正確，只有兩處數據有誤。
「只有通過面試，才可以獲得取錄。陳先生通過了面試，所以他一定會獲得取錄。」這段推論：
正確，因為通過面試是獲得取錄的充分條件
錯誤，因為通過面試只是獲得取錄的必要條件，通過了並不保證獲得取錄
正確，因為「只有……才……」與「只要……就……」的意思相同
錯誤，因為陳先生其實沒有通過面試
下列哪一句有歧義？
三個部門的主管出席了會議。
三名部門主管出席了會議。
部門主管共三人出席了會議。
來自三個部門的主管出席了會議。
Sections you finish are checked off in the contents.