use the past indefinite or the present prfet instead of the infinitives in brackets
How long you(to know ) him? HE (to livr) in LENIGRAD for 2 years and then (to go) to Sibiria
When he (to arrive ) ?
I (to read )this book when i was at school
i cant go with you as i (not to finish)my work

How long have you known him? He had lived in LENIGRAD for 2 years and then went to Siberia. When did he arrive? I read this book when I was at school. I can't go with you as I have not finished my work.