He last saw her two weeks ago.
He didn’t see her two weeks ago.
He saw her for two weeks.
He hasn’t seen her for two weeks.
He has seen her for two weeks.
Knowledge: Present perfect tense
Usage: the present perfect describes an event that started in the past, is still related or has a result in the present, without mentioning when the action happened.
Usually used with: for + time period / since + time point.
Synonymous structure: S + last + V-past simple + time period + ago: The last time someone did something was….
= S + haven’t / hasn’t + P2 + for + time: How long has it been since someone has been doing nothing
=> He last saw her two weeks ago.
A. He didn’t see her two weeks ago. => wrong meaning (2 weeks ago met)
B. He saw her for two weeks. => wrong meaning
C. He hasn’t seen her for two weeks. (2 weeks ago, we met, but we haven’t seen each other since 2 weeks)
D. He’s been seeing her for two weeks. => wrong meaning