Grammar Guide: Present Perfect vs Simple Past

"I have seen him yesterday." This single error type appears in almost every newcomer’s speaking and writing, and it directly lowers CLB grammar accuracy. The good news: one core idea resolves most of the confusion.

The Core Idea: Finished Time vs Connected to Now

Simple past = a finished action at a finished time. The time is over and disconnected from now.
Present perfect = the action connects to the present — either the time period is unfinished, or the result/experience matters now, not when it happened.

• "I visited Toronto in 2019." (finished time — 2019 is over)
• "I have visited Toronto." (experience — the point is that I have the experience, not when)
• "I have lived here for three years." (started in the past, still true now)

The Forms

Signal Words That Tell You Which to Use

Key rule: a specific finished time (yesterday, last year, at 5 p.m.) forces the simple past. You cannot say "I have done it yesterday."

For vs Since

• for + length of time: "for two years," "for ten minutes."
• since + starting point: "since 2021," "since Monday."
• Both typically take present perfect when the situation continues: "I have worked here since March."

The Errors That Cost Marks

1. Present perfect + finished time: ✗ "I have arrived last night." → ✓ "I arrived last night."
2. Simple past for life experience (no time): ✗ "Did you ever eat poutine?" → ✓ "Have you ever eaten poutine?"
3. Simple past for an ongoing situation: ✗ "I live here for two years." → ✓ "I have lived here for two years."
4. Wrong participle: ✗ "I have went." → ✓ "I have gone."

A Quick Self-Test

Choose the correct form:

• "She ___ (finish) the report yesterday." → finished (finished time)
• "I ___ (not / see) that movie." → haven’t seen (experience, no time)
• "They ___ (live) in Calgary since 2018." → have lived (since + continues now)
• "We ___ (go) to the lake last summer." → went (finished time)

How to Master It Fast

Do not "study tenses" broadly. For one week, every time you talk about the past, pause and ask: Is the time finished, or does it connect to now? Apply only this rule, get feedback on your sentences, and the pattern becomes automatic far faster than memorising tables.

Bottom Line

Most present perfect vs simple past errors disappear once you internalise one question: finished time → simple past; connected to now (unfinished time, experience, result) → present perfect. Watch the signal words, never pair present perfect with a finished time, and drill it in your own real sentences.