Present Perfect - Fill in with since or for

My father has worked as an engineer _____________ then.

My sister has known her friend ___________ five years.

I have not seen my aunt ____________ last summer.

I have not talked to him _____________ a long time.

I have not talked to her ___________ last year.

I have learned these words ____________ three hours.

Jason has taught music ___________ twenty years.

My mother hasn't spoken to me ______________ two days.

My brother has had his new mountain bike ___________ last week.

My friend Marco has written me two letters ____________ I saw him last summer.