Complete the sentences using the present perfect.
1 . I_____________ (work) in this department since 2015.
2. They__________ (volunteer) at the hospital since June.
3. I __________ (not/see) my cousin for a long time.
4. Kim__________ (know) Amy for many years.
5. We_________ (live) in this neighborhood since 2012.
6. I___________ (be) sick. I__________ (not/go) to class since last year.