Qual è la differenza tra for the past 20 years e over the past 20 years e in the past 20 years ?Sentiti libero di rispondere con un esempio.

"For the past 20 years" means that something has happened without stopping. Or something has happened repeatedly. For example:
- For the past 20 years, I have lived in Michigan. (= From 2000 to today I have lived in Michigan. Since the year 2000, I have not lived anywhere else.)
- For the past 20 years, I have been teaching people English grammar.

"Over the past 20 years" means the same thing, but it is often used in negative or unhappy statements. For example:
- Over the past 20 years, the price of petrol has steadily increased.
- Over the past 20 years, I have repeatedly tried to (do something) and failed every time.

"In the past 20 years" is used for things that happened once or a few times - or didn't happen. For example:
- I haven't been to Germany in the past 20 years.
- I haven't seen a rabbit in the past 20 years.
- I've only seen one hawk in the past 20 years.