Here's the answer:
“ich habe zwei Monate lang in Japan studiert”
Watch a real native speaker say it:
Here's how it sounds in a textbook:
You could also say:
- in Japan habe ich zwei Monate lang studiert
- zwei Monate lang habe ich in Japan studiert
Fun fact: the hundreds of thousands of people learning German with Memrise get this phrase correct 98.43% of the time!
