Question

What .... you doing when they arrived I ... reading the peper​

Answer 1

Ответ:

What were you doing when they arrived?

I was reading the paper.

Объяснение:

Чем ты занимался, когда они пришли?

Я читал газету.

Действие длилось в прошлом, но было прервано.

Answer 2

It seems like there might be some missing words or typos in your sentence. It should be something like:

"What were you doing when they arrived? I was reading the paper."

This sentence is in the past continuous tense and describes two simultaneous actions in the past: "you were reading the paper" and "they arrived."