1.He(have)was having dinner when his friend called.
2.She(cook)is cooking at the moment. That's why she can't answer the phone.
3.Jane(leave)left just a few minutes ago.
4.She(be) has been extremely quiet since her husband died.
5.A:"Do you know that Mrs.Janet has worked(work) here for sixteen years?
" B:"I thought she started (start) working here ten years ago".