I have to say, this is probably the best birthday dinner ever. 請問 ever 在句中是什麼詞，副詞? 一般ever 是什麼情況下用?

This is the best dinner I have ever (adv) had.
This is the best dinner as if I would ever (adv) had.

ever [副詞] 釋義4.((加強語氣))到底;說來,不管怎樣;大概,完全[絕對](…沒有)．
(1)((用於疑問詞之後)) 例1. Where ever have you been?
●(2)((比較級·最高級的強 調))
例1. You're looking lovelier than ever.
(從未看過妳這麼漂亮。//こんなにきれいな君は見たことがないよ。)
例2. the most remarkable election ever
(從未出現這麼顯眼的選舉 // いまだかつてなく注目すべき選挙)
🔴(本題)例3. I have to say, this is probably the best birthday dinner ever. (我必須說，這可能是至今最棒的生日晚宴。)
# ever 其餘的釋義，請參閱辭典為宜。

The word "ever" is an adverb. We use it after comparatives and superlatives to emphasize the degree to which something is true or when we are comparing a present situation with the past or the future.

For example, 'Fear Of Music" remains among the best albums ever for many music fans.

see p.527 Collins Cobuild English Dictionary for Advanced Learners (third edition) ever #3

I have to say this is probably the best birthday dinner ever. 是在與「過去」做比較。因為這句子裡用了形容詞good的最高級the best。副詞ever修飾述部。ever =有史以來。

ever的其它用法，請參見上述的英英字典，共有十四個解釋及相關例句。

我要說，這是我這輩子最棒的生日了!! ever 最....