There are two kinds of determiners:

• The first kind identifies things: articles (a/an, the), possessives (my, your, our…), demonstratives (this, that, these, those)
• The second kind are quantifiers, expressing how much or how many: some, any, no; each, every, either, neither; much, many, more, most; (a) little, less, least; (a) few, fewer, fewest; enough, several; all, both, half; another, other

• Each and every are used with singular nouns. Each can be used to talk about two or more people or things. Every is used to talk about three or more: Every/Each time I come to your house it looks different.
• In many cases, each and every can both be used with little difference in meaning.
• We prefer each if we are thinking of people or things separately, one at a time. We use every if we are thinking of the things or people all together as a group.

• We use a/an to refer to a singular countable noun which is indefinite — either we don't know which one, or it doesn't matter which one: They live in a lovely house. She's expecting a baby.
• We use a/an with professions: She's a lawyer.

• We use the before a singular or plural noun, when both the speaker and listener know which noun is being referred to: They live in the green house opposite the library.
• We use the when there is only one: the world, the River Thames, the Atlantic
• We use the for certain places which are institutions — which particular place isn't important: We went to the cinema/the theatre last night.
• a followed by the: We use a to introduce something for the first time. When we refer to it again, we use the.

• We use no article with plural and uncountable nouns when talking about things in general: (–) Computers have changed our lives. (–) Love is eternal.
• We use no article with meals: Have you had (–) lunch yet? Come round for (–) dinner tonight.
• But we use an article when describing a particular meal: We had a lovely lunch in an Italian restaurant.