Нужно поставить либо в past simple либо в past continuous.
1) What subject ... (you, study) when school finished yesterday?
2) What was your mum doing when you ... (get up) this morning?
3) What ... (you, wear) when you had breakfast today?
4) ... (you, meet) your friends while you were coming to school this morning?
5) Wgat were you doing when your Engkish teacher ... (arrive) in the classroom?
6) Did you use a computar while you ... (do) your homework last weekend?