?if ever是一個常用的短語，可以用來表示“如果曾經”，“如果有一天”，“萬一”等含義。它通常用于虛擬語氣或假設語句中，表達某種可能性或假設情況下的結果。

用法：

if ever通常放在句首，后接一個陳述句或虛擬語氣句子。它可以與現在時、過去時、將來時等各種時態連用。

例句1-5句且中英對照：

1. If ever you need my help, just give me a call.

如果你需要我的幫助，隨時給我打。

2. If I ever see him again, I will tell him the truth.

如果我再見到他，我會告訴他。

3. If we ever get lost in the woods, we can use a compass to find our way back.

如果我們迷路了，我們可以使用指南針找回去。

4. If she ever becomes famous, I will be proud of her.

如果她成名了，我會為她感到驕傲。

5. If he ever finds out about this, he will be very angry.

如果他知道了這件事，他會非常生氣。

同義詞及用法：

1. In case

意思：以防萬一

例句：In case of fire, please use the emergency exit.

2. Should

意思：萬一

例句：Should you need any assistance, please do not hesitate to contact us.

3. If perchance

意思：萬一

例句：If perchance he calls, please let me know.

4. In the event that

意思：如果發生

例句：In the event that the flight is delayed, we will provide you with accommodation.

5. On the off chance that

意思：萬一，偶然的情況下

例句：On the off chance that you have some free time, we could go for a walk together.