No article with institutions when referring to their primary purpose (not the buildings).

Use "the" with musical instruments.

Use "the" when both the speaker and listener know what is being referred to. Also homework is an uncountable noun, so „a“ is impossible to use.

Use "the" with names of mountain ranges.

Use "the" to talk about specific things in a group.

Use "a" for expressions of frequency (e.g., once a year, twice a week).

Use "the" to refer to a specific movie already mentioned or known.

Use "the" to talk about something mentioned earlier or known specifically.

Use "the" with places that are unique in a given context (e.g., cinema).

Use "a" when mentioning something for the first time. „U“ in UFO is pronounced as [ju:] that’s why we use „a“ and not „an“.

Use "the" for specific meals when referring to a particular meal of the day (but we don’t use “a”).

Use "an" before singular countable nouns starting with a vowel sound.

We are talking about all tigers, but later "the" is used to refer to a specific tiger.

No article with uncountable nouns used in a general sense.

Use "a" in exclamations starting with "What" followed by a singular noun.

Use "an" before singular countable nouns starting with a vowel sound when we mean “one”.

Use "a/an" when talking about professions.

Use "the" when talking about a specific building, not its purpose.

Use "an" before singular countable nouns starting with a vowel sound. We usually use “a/an” with jobs.

Use "a" when referring to one item from a group of similar items.

Use "the" to specify a particular group of people or things.

Use "a" for singular countable nouns when mentioning them for the first time and we don’t mean a specific one.

Use "the" with names of countries that include words like "States" or "Republic."

No article for general meals (e.g., breakfast, lunch, dinner).

Use "a" for singular countable nouns mentioned for the first time.