Since or for. 1) he has been a tailor ... he finished school/2) they have known each other ... ages. 3) i have had these shoes ... last week.

Since - "с", "с какого-то момента"

for - "в течение какого-то времени"

1) He has been a tailor SINCE he finished school. - Он работает портным с того момента, как закончил школу.

2) They have known each other FOR ages. - Они знают друг друга целую вечность. (дословно - в течение долгих лет)

3) I have had these shoes SINCE last week. - У меня эти ботинки с прошлой недели. (то есть "я их приобрел на прошлой неделе, и с того момента они у меня")