11.   The most difficult strategic question was whether sea power was any longer the foundation upon which the Three Pillars could continue to stand.

12.   The second is the more difficult question.

13.   The use of animals in scientific tests raises difficult ethical questions.

14.   These operations can save lives, but they raise difficult questions about animal rights.

15.   They asked me quite a lot of difficult questions about my job.

16.   This is perhaps the most difficult question one can answer.

17.   To what extent students on such a degree would also need to read poetry in another language is a difficult question.

18.   There were some difficult questions but I managed to muddle through.

19.   Politically and economically this is an extremely difficult question.

20.   Politicians need to do more than provide glib answers to difficult questions.