In English, we might say to say Andi buys a shirt and jacket, leaving out the extra "a".
Yes that shoukd be correct as well
Yes, but it is graded as fail.
It's accepted now
Can't this be plural? Andi buys shirts and jackets? Or a combination. Andi buys shirts and a jacket. Andi buys a shirt and jackets.
Andi buying a shirt and a jacket ... What's wrong with that?
Technically nothing. That would be used in the description of a video or an image. But that's not what you'd say in conversation or write. It'd need to be Andi "is" buying a shirt and a jacket.