11.   Seeing her frown, Giles turned to look behind him.

12.   If one looks behind what is being said by both sides, there is in fact little that divides them.

13.   As I look behind me the queue was getting bigger and bigger..

14.   And, for the first time in a while, it has become easier than looking behind.

15.   As he dribbled, he looked behind him toward the Duke bench once.

16.   As you watch the games, look behind the athletic feats to try to see which athletes master the forces of science.

17.   After I had passed it, I looked behind me and saw some black smoke.

18.   But I looked behind me, and lots of guys were snoozing.

19.   But she also looked behind.

20.   But still, my heart leaped when his father told him to look behind the desk.