Prepositions of time – here’s a list of the time words that need ‘on’, ‘in’, ‘at’ and some that don’t need any preposition. Be careful – many students of English use ‘on’ with months (it should be ‘in’), or put a preposition before ‘next’ when we don’t need one.
General
| In | (year, month) | In 1989, in December |
| On | (day, date) | On monday, on Dec. 14, 2001 |
| At | (time) | At 7:00, at 8:30 |
| During | (decade, long time period) | During the 1960s, during the 20th Century |
Specific Time: “When?” (Use simple tenses.)
| When did you eat your breakfast? | I ate my breakfast at 9:00. |
| When were you born? | I was born in 1979. |
| When is your birthday party? | My birthday party is on Friday. |
| When will you graduate? | I wil graduate in June. |
Ongoing Action
Mr. Barnes is watching television now.
While he was watching television, the phone rang.
He will be watching television tonight when his wife gets home.
Duration: “How Long?”
| How long have you been in the U.S.? | I have been here since 1999/for two years. |
| How long were you in California? | I was in California for three weeks. |
| How long will you be in Maine? | I will be there for a month. |
Completed Action
I have finished my homework already. (before now)
After I had finished my homework, I started to cook dinner.
I will have finished my homework, when I start to cook dinner.
Notes:
| In + (amount of time) usually refers to the future: | I will see you in two days (from now). |
| But it can also indicate a length of time: | I finished the job in two hours. |
Ago follows time word(s) and is used to indicate the amount of time before the present:
| I called her two weeks ago. | She returned my call five minutes ago. |
Words indicating actions occurring at the “same” time (or nearly the same time)
| When | When I was in high school, I had a car. |
| As soon as | As soon as I got to the theater, I looked for a seat. |
| Once | Once I finish my geometry, I will start studying chemistry. |
| The moment (that) | The moment (that) I saw her, I knew who she was. |
Words indicating actions occurring at “different” times
| Before | Before my husband left, I had already packed his bags. |
| After | After she eats her dinner, Ms. Warner will go shopping. |
| By the time | By the time I get to Denver, I will have traveled 200 miles. |
| Until | I cleaned the house until my wife came home. |