We use phrases with prepositions as time adverbials:
We use
at with:
clock times:
at seven o'clock
at nine thirty
at ten fifteen
mealtimes:
at breakfast
at lunchtime
at teatime
these phrases:
at night
at the weekend
at Ramadhan
We use
in with:
Seasons of the year:
in "the" spring
summer
winter
years · centuries · decades:
in 2009
in 1998
in the 60's
months:
in January
in February
in April
parts of the day:
in the morning
in the afternoon
in the evening
We use
on with:
days:
on Monday · etc.
on my birthday
dates:
on the thirty-first of July
on June the fifteenth
We say
at night when we are talking about all of the night:
When there is no moon, it is very dark
at night.
He sleeps during the day and works
at night.
but we say
in the night when we are talking about
a specific time during the night:
He woke up twice
in the night.
I heard a funny noise
in the night.
We often use a noun phrase as a time adverbial:
yesterday
last week
month
year
last Satuday
the day before yesterday
one day · week · month
the other day · week · month
today
this week
month
year
this Tuesday
-
-
-
tomorrow
next week
month
year
next Friday
the day after tomorrow
-
-
We can put time phrases together:
We will meet
next week at six o'clock on Monday.
I heard a funny noise
at about eleven o'clock last night.
It happened last week
at seven o'clock on Monday night.
We use
ago with the past simple to say
how long before the time of speaking something happened:
I saw Jim about
three weeks ago.
We arrived
a few minutes ago.
We use in with a future form to say
how long after the time of speaking something will happen:
I'll see you
in a month.
Our train's leaving
in five minutes.