31.   Roads once built of gravel are now often built of ice and melt away in the spring thaw, leaving few traces on the spongy ground.

32.   Some, like palm wine, would have evaporated or disintegrated and left little trace.

33.   The awesome destruction of the fires appeared to be the work of a cunning arsonist using a mysterious fuel that left no trace.

34.   The copper cladding of military bullets leaves traces on bone when it corrodes, depositing indelible green stains that help forensic experts reconstruct events.

35.   The fact that they found it means that it left some trace.

36.   The instructor, Tony Burrell, lectured on safeguarding the environment and leaving no traces of our rides.

37.   The Phoenicians, the Greeks, the Romans, the Ottoman Turks, the British and the French all left their traces before being driven out.

38.   The pair moved quickly, leaving no traces.

39.   The question of what we lose in a lifetime, and what traces we leave behind, lies at the heart of this exquisite and moving family saga.

40.   The terrain between the two points would have left some trace on her shoes or socks, Brand said.