What were they doing at six p.m.yesterday evening?怎么回答?

What were they doing at six p.m.yesterday evening?怎么回答?

那要根据具体情况了
可以说：They were having dinner.或者是 They were watching TV.都可以
只不过要用过去进行时

昨天下午六天他们在做什么？
they were reading book