Past tense,past perfect tense,present perfect tense in english

Question

Are they possible if I use it in past events? Which are British English and which are American English

E.g.

They have just/already/never eaten 2 biscuits 2 minutes ago.

They had just/already/never eaten 2 biscuits.

They just/already/never ate 2 biscuits.

They haven't written/eaten yet.

They didn't write/eat yet.

They hadn't eaten/written yet.

So, which are British English and American English in past events?

E.g.

I ate/drank/sang yesterday.

I have eaten/drunk/sung yesterday.

I had eaten/drunk/sung yesterday.

Could you give me the explanations about this topic? I await for your explanations, thanks!

Answer 1

I ate yesterday, simple past. I have eaten many times--cannot use this tense with specific time. Many times is not specific. I had eaten yesterday, when my friend appeared at the door. Past perfect for a completed action in the past, when some other action occurred.

They haven't written yet. Time is not specific, and one uses present perfect.

I would leave it to my British colleagues to discuss biscuits. We eat them here, but the term is not used often.

They ate two biscuits two minutes ago. Simple past with specific time.