在 u 开头的单词前面，用 a 还是 an

The choice between "a" and "an" is always based on the sound that comes next, not on the category of the letter.

We say and write "a university" because "university" starts with the consonant sound of "y," even though its first letter when written is the vowel "u."

by Egmont

出处 https://forum.wordreference.com/threads/an-uk-account-or-a-uk-account.2950255/