Use a before a word which begins with a
consonant sound. Use an before a word which begins with a vowel
sound.
Remember that it is always the first sound
of the next word which is important, not the first letter.
Compare : "an Englishman" but "a
European", "an orange" but "a one-way street", "an
umbrella" but "a university".
จะใช้ a หรือ an ดี ?
คำที่มักใช้ผิด