Question

when we use preposition by

Answer 1

in : this is used to express events taking place during lengthy periods of time, such as a month or year, for example: “They first moved to the country in 1978.” On: Like “in” this is used for specific points in time – in this case, you use this preposition to indicate particular dates or days.

Answer 2

Preposition by___meaning and use.
*By* is usually a preposition but it can also be used as an adverb........