Re: [文法] Not or合併用法
: 看到公司文件有一個句型用法，突然搞不懂，如下
: A is not B or C…
: 這樣到底是
: 1. A不是B或A不是C的話…
: 2. A不是B或A是C的話…
: 3.文法有問題
: 再麻煩各位幫忙解決疑惑 謝謝！
A is not B or C.
若B和C是對等的（都是形容詞、都是名詞...)
則這個句子會被解讀為
A is not (B or C).
例：
The dog is not brown or black.
The food is not healthy or delicious.
I am not detached or remote.
It's not on the table or in the cupboard.
Our main need is not food or money. It is education.
由笛摩根定理，not (B or C) 等價於 (not B) AND (not C)
以下為笛摩根定理的證明
（沒興趣的話可以跳過）
Let x be an arbitrary element of (B U C)',
then x ∈ (B U C)'
→ x not∈ (B U C)
→ x not∈ B and x not∈ C
→x ∈ B' and x ∈ C'
→ x ∈ B' ∩ C'
Therefore, (B U C)' ⊆ B' ∩ C' ……………(i)
Again, let y be an arbitrary element of B' ∩ C',
then y ∈ B' ∩ C'
→ y ∈ B' and y ∈ C'
→ y not∈ B and y not∈ C
→ y not∈ (B U C)
→ y ∈ (B U C)'
Therefore, B' ∩ C' ⊆ (B U C)' ……………(ii)
Combining (i) and (ii), we get (B U C)' = B' ∩ C'
從文氏圖上看比較直觀
https://i.imgur.com/dNIxVsE.jpg
所以
A is not (B or C).
= A is not B AND A is not C.
再看原本的例子
The dog is not brown or black.
= The dog is not brown AND the dog is not black.
The food is not healthy or delicious.
= The food is not healthy AND the food is not delicious.
I am not detached or remote.
= I am not detached AND I am not remote.
It's not on the table or in the cupboard.
= It's not on the table AND it's not in the cupboard.
Our main need is not food or money.
= Our main need is not food AND our main need is not money.
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※ 編輯: LongboardDC (114.39.207.124 臺灣), 09/17/2021 01:24:43
※ 編輯: LongboardDC (114.39.207.124 臺灣), 09/17/2021 01:26:14
※ 編輯: LongboardDC (114.39.207.124 臺灣), 09/17/2021 01:29:02
※ 編輯: LongboardDC (116.89.134.37 臺灣), 09/17/2021 02:26:28
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