Time expressions are used to indicate the time at / during which an action took place. Common time expressions include:

Present forms: everyday, on Fridays, at the moment, now, as well as always, usually, sometimes (for present habits and routines)

Past forms: when I was ..., last week, day, year, etc., yesterday, ago (two weeks ago, three years ago, four months ago, etc.)

Future forms: next week, year, etc., tomorrow, by (the end of the week, Thursday, next year, etc.) in X time (in two weeks time, in four months time, etc.)