Пожалуйста помогите выполнить эти упражнения.

since-1,4,6,7,9,12,13,14for-2,3,5,8,10,11,15I have known Ben since my childhoodWhen have you started to work?-------- since he entered the------- have changed a lot since the last time------- hasn"t been at work for week+How long have you owned this flatI have taken part ------------------our secretary for several years+