ПОМОГИТЕ ПОЖАЛУЙСТА. Past Indefinite Tense, Present Perfect, Past Continuous  or Present Perfect Continuous?

It …(rain) when I went out into the street . He broke a tooth when he … (eat) a sandwich. He … (write) about a hundred novels (He is alive and can write more). How long …they (live) in Moscow? We … (begin) the experiment three days ago. 

It was raining when I went out into the street.He broke a tooth when he was eating a sandwich.He have written about hundreds novels.How long have they been living in Moscow.We began the experiment three days ago.