21.   I might be able to pop in for about half an hour.

22.   I remember a short, rhythmically complex passage patiently unpicked and reconstituted over half an hour.

23.   In half an hour only one small truck passed, a satellite dish rocking in the back.

24.   It took us half an hour to find somewhere to park.

25.   It will take at least half an hour to park your car and get to the ticket booths.

26.   Less than half an hour later she cleaned the brush in white spirit and pressed the lid of the tin noiselessly down.

27.   Meet me back here in half an hour - I just need to finish up a couple of things.

28.   Michael left the office about half an hour ago.

29.   My hospital appointment lasted half an hour.

30.   Roll in bread crumbs and grill for half an hour.