after / later
Use after + phrase, and use later alone (at the end of a sentence or phrase).
*I’ll call you later.
I’ll call you after I get home from work.
*First he bought a new car. Two weeks later, he bought a new motorcycle.
He bought a new motorcycle two weeks after he bought a car.
You can say “later + time period” to refer to an unspecified time in the future, for example:
*I’ll finish the project later this week.
*We’ll go on vacation later this year.
Never end a sentence with “after.” Instead, you can use “afterwards”
Did you go straight home after the baseball game?”
“No, we went out for drinks after.”
“No, we went out for drinks afterwards.““Did you go straight home after the baseball game?”
“No, we went out for drinks after.”
“No, we went out for drinks afterwards.“
ago / before
Use ago to talk about past times in reference to the current moment.
Use before to talk about past times in reference to another moment in the past.
by / until
Use by for one specific event that will happen before a certain time in the future. Use until for a continuous event that will continue and then stop at a certain time in the future.
*Please send me the information by Monday.
*He’s staying in London until the 30th.
during / while
Both during and while mean that something happens at the same time as something else.
Use during + noun.
*She cried during the movie.
Use while + subject + verb, or while + gerund.
*She cried while she was watching the movie.
*She cried while watching the movie.
from… to / till / until
We use from + to / till / until to define the beginning and end of a time period.
*The museum is open from 8 AM to 4 PM.
*Jack will be on vacation from tomorrow until next Friday.
*I studied English from 2001 till 2004.
on / in / at
Use in for centuries, decades, years, seasons, and months:
*In the 18th century
*In the 1960s
*In 2001
*In the summer
*In October
Use on for days:
*On Friday
*On March 15th.
*On my birthday
*On the weekend
Use at for times:
*At 3:30.
*At noon.
*At quarter past four.
Be careful with morning, afternoon, evening, and night!
*In the morning
*In the afternoon
*In the evening
*At night
past / to
We can use these prepositions with minutes in relation to the hour:
*3:50 = Ten to four
*6:15 = Quarter past six
for / since
For is used for a period of time, and since is used to reference a specific point in time.
*I’ve been waiting for three hours.
I’ve been waiting since ten o’clock.
*We’ve lived here for four years.
We’ve lived here since 2008.
*She’s been working there for six months.
She’s been working there since she graduated from college.
as soon as / as long as
As soon as means “immediately after another event.”
*We’ll call you as soon as we arrive.
(if we arrive at 8:00, we’ll call you at 8:05)
As long as means “for the period of time” or “on the condition that”:
*I stayed awake for as long as I could. (period of time)
*I’ll take the job as long as I have the freedom to work from home a few days a week. (condition)