Начинающих 1 - Союзы

used to connect two words, phrases, or sentences referring to related things

и

used for introducing the reason of something

потому что

used for introducing a word, phrase, or idea that is different to what has already been said

но

used to connect alternatives or introduce another possibility

или

used to introduce a statement

это

used to indicate that two things happen at the same time or during something else

когда

used to refer to a particular situation, stage, or place

где, куда