1) Claire has already left.
2) I am very busy now. I have told you several times.
3) Sam hasn't heard...
4) Has the student already read the text?
6) She has been ill since last Friday.
8) What has happened?
10) I have been living in this house since 2 years.
12) I haven't recently seen Mike.
13) Denny arrived...
14) When did you met him?
15) The doctor has just gone out.