Prepositions in expressions of time

Preposition	Use	Examples
in	in months	in July; in September
	year	in 1985; in 1999
	seasons	in summer; in the summer of 69
	part of the day	in the morning; in the afternoon; in the evening
	duration	in a minute; in two weeks
at	part of the day	at night
	time of day	at 6 o'clock; at midnight
	celebrations	at Christmas; at Easter
	fixed phrases	at the end of the week at the same time
on	days of the week	on Sunday; on Friday
	date	on the 25th of December*
	special holidays	on Good Friday; on Easter Sunday; on my birthday
	a special part of a day	on the morning of September the 11th*
after	later than sth.	after school
ago	how far sth. happened (in the past)	6 years ago
before	earlier than sth.	before Christmas
between	time that separates two points	between Monday and Friday
by	not later than a special time	by Thursday
during	through the whole of a period of time	during the holidays
for	period of time	for three weeks
from ... to from... till/until	two points form a period	from Monday to Wednesday from Monday till Wednesday from Monday until Wednesday
past	time of the day	23 minutes past 6 (6:23)
since	point of time	since Monday
till/until	no later than a special time	till tomorrow until tomorrow
to	time of the day	23 minutes to 6 (5:37)
up to	not more than a special time	up to 6 hours a day
within	during a period of time	within a day