11.   Recent theoretical work has clarified two possible causes of ageing.

12.   There are many possible causes of infertility in women.

13.   What are the possible causes of work inhibition?

14.   What then are the possible causes of conflict within organisations?

15.   HOOK The commission sfinal report will home in on the possible causes of the crash.

16.   A number of theories were put forward at the time about the possible causes of his death.

17.   Officials have not yet ruled out sabotage as a possible cause of the crash.

18.   The origins of the lower critical phase separation phenomenon in polymer blends are not yet clearly understood and three possible causes have been proposed.