Articles: a / an / the / no article

English has no grammatical gender: the for everything definite.

• a before a consonant sound, an before a vowel sound: a book, a university, an apple, an hour.
• No article for general ideas in the plural or uncountable: Dogs are friendly. I like music.
• No article before most countries, cities, meals, languages: in Switzerland, at breakfast. But: the USA, the UK.
• Jobs take “a / an”: I'm an engineer.