Past time expressions tell the listener when an event happened and often help determine which tense is natural. Expressions such as yesterday, last week and two years ago usually locate a finished time before now, so they commonly appear with the past simple.
The key is not memorizing isolated phrases. Learn how each expression places an event on a timeline and where it normally sits in a sentence.
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Finished-time expressions and the past simple
| Expression | Example | Timeline meaning |
|---|---|---|
| yesterday | I called Maya yesterday. | The day before today |
| last night | We watched the match last night. | The previous night |
| three days ago | The parcel arrived three days ago. | Three days before now |
| in 2024 | She moved to Ankara in 2024. | Within a finished calendar year |
| on Monday | They met on Monday. | A particular Monday understood from context |
These expressions usually make the reference time complete. For that reason, “I saw him yesterday” is natural, while “I have seen him yesterday” is not standard in most varieties of English. The present perfect connects past experience to the present without naming a finished past time.
Last and ago use different reference points
Last identifies the previous completed period: last week, last month, last summer. Do not normally add a preposition before it. Say “We travelled last summer,” not “in last summer.”
Ago counts backward from now and follows the amount of time: ten minutes ago, six months ago, a long time ago. Compare these sentences:
“I started this course last September” identifies a calendar period. “I started this course six months ago” measures the distance between the start and now. Both can be correct, but they organize time differently.
In, on and at with past dates
Use in with years, months and longer periods: in 2019, in April, in the 1990s. Use on with days and dates: on Friday, on 12 May, on my birthday. Use at with clock times and certain fixed expressions: at 8:30, at midnight, at the time.
No preposition is needed before yesterday, last or ago. This gives us “yesterday morning,” “last Friday” and “two hours ago.”
Where the time expression goes
The end of the sentence is the neutral position: “The meeting finished at four.” A time expression can move to the beginning when it frames the story or creates contrast: “Last year, the team worked remotely. This year, everyone returned to the office.”
Do not separate a verb from its object without a reason. “I finished the report yesterday” is smoother than “I finished yesterday the report.”
Past simple, past continuous and past perfect
A time phrase does not select the tense by itself. The speaker’s view of the event also matters.
Past simple: At nine, I answered the first email.
Past continuous: At nine, I was answering emails.
Past perfect: By nine, I had answered all the urgent emails.
The first sentence presents one completed action. The second shows an activity in progress at that time. The third looks back from a later past point and emphasizes completion before nine.
When and while in a short narrative
When can introduce the event that interrupts or changes a situation: “I was walking home when it started to rain.” While often highlights two activities continuing at the same time: “While I was cooking, Sam was setting the table.” These are tendencies, not mechanical rules, so focus on the relationship between events.
Common corrections
| Problem | Natural correction | Reason |
|---|---|---|
| I went there before two days. | I went there two days ago. | Ago counts back from now. |
| We met in last week. | We met last week. | Last does not need in. |
| She has arrived yesterday. | She arrived yesterday. | Yesterday is a finished past time. |
| He called me in Monday. | He called me on Monday. | Use on with days. |
Short practice
Complete the story with appropriate expressions: “I joined the company ___ 2022. ___ Monday, my manager asked me to present a project that we had completed two weeks ___. I was checking the final numbers ___ she called.”
A natural answer is: “in 2022,” “last Monday” or “on Monday,” “two weeks earlier,” and “when she called.” More than one answer may work if the surrounding timeline changes.
To improve, write six true sentences about a finished week. Use yesterday, last, ago, in, on and when once each. Then explain the timeline aloud. If you want to check the overall difficulty of your grammar practice, begin with the Global English Test and choose tasks close to your estimated level.
