By upper intermediate level, students have normally learnt the following three grammar structures involving past participle verbs (eaten, given, seen, known, taken, …):
- “present perfect” – e.g. I have seen that movie already.
- “past perfect” – e.g. Before I moved to Japan, I had studied Japanese for 2 years.
- “3rd conditional” – e.g. If you had told me it was your birthday today, I would have given you a present.
Remember this one rule for all three structures to avoid a common grammatical mistake:
- Rule: Any time you use the helping verb ‘have’ or ‘had’ in front of a main verb, the main verb must be in the past participle form (never the past simple form).
For example, depending on which is required, use either:
“have taken” or “had taken“
“have took” or “had took“.