英文文法一急問 成句文法無錯？

We can achieve a zero-discriminating community "if and only if" we let go all stereotypes and treat every individual fairly.
應該用if and only if帶出條件，這條件是充分且必要的。

Witches are real if and only if there are criteria for identifying witches.(句尾通常是焦點： the principle of end-focus，所以新和重要的資訊通常在句尾出現)

only當否定詞使用：Only in case of emergency can you use this exit.將否定的副詞（片語）置於句首時，必須倒裝主句。

if only的用法：We must respect him if only because he is honesty. = We must respect him if only for his honesty.＝即使只為了他的誠實這一點，我們也必須尊敬他。
If only she were here! =要是她在這裡就好了！（假設語氣動詞）
If only I had taken her advice!=要是我當時聽了她的建議就好了！（假設語氣動詞）

只有我們拋棄陳規陋習，並平等地對待每個個體，才能達成一個零歧視的社區。
我覺得您這個only if的倒裝句寫得很好啊

Only if we all let go of any stereotypes and treat every individual fairly can we achieve a zero-discrimination community.
Only if we all let go of any stereotypes and treat every individual fairly==The whole sentence is being treated as a subject;
can we achieve a zero-discrimination community==This is predicative and objective phrases in an interrogative manner.
Yip