4b Complete the dialogues. Use the Present perfect.
A Hi! How are you? I (not / see) ___ you since your birthday party.
B I (be) ___ very busy.
A How long (she / teach) ___ at that school?
B She (work) ___ there for years and years.
A (you / know) ___ that girl for a long time?
B No, we (just / make) ___ friends.
A Why aren't you laughing at my joke?
B Because I (already / hear) ___ it.
A What do you think of that book?
B I don't know. I (not / read) ___ it yet.