Exercise.Use the Present Perfect or the Present Perfect Continuous.
1) Look! Somebody … (break) the window. 2) I wonder if John (forget) my number. I …
(expect) him to call for the past two hours. 3) You look very upset What … (happen)? 4) You … (not / finish) that book yet? You … (read) it since Monday. 5) The meat must be nearly ready. I … (cook) it for nearly an hour. 6) What you ... (do) for the last two hours? -I ... (sit) here working at this problem.