The A-class vowels make some variation of the "a" sound in English. They are:
אַ
A patah is a short vowel and is pronounced as the a in father.
אָ
A qamats is a long vowel and is pronounced as the a in father.
אֲ
A hataf-patah is a very short or reduced vowel and is pronounced as the a in anniversary.
דָּה
A qamats-hey is pronounced as the a in father.