A lot of people learned in primary (elementary) school to use A before a consonant and An before a vowel. That’s a rough way of looking at it which covers the basics. But a more accurate way of dealing with the rule is that it’s “a” before a consonant SOUND and “an” before a vowel sound. That’s why you say, “Fred just received an MBA.” Because the word MBA stars with the sound of an E (em bee ay.
This is why people get so confused with words starting with an “h” because quite often the “h” is silent. An hour, for example but a horse. The same with words starting with “O”. Is it an “O” sound or a “W” sound? A one-way ticket to Paris, but an only child.
See, it’s not so hard after all.
Helen is available to line edit and/ or content edit fiction and non-fiction. Rates on application.