1. I must think out this difficult question.

2. He embarrassed me with a difficult question.

3. 4 He embarrassed me with a difficult question.

4. 1 I must think out this difficult question.

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

6. The control of anchorage has been a difficult question orthodontics.

7. When you face a difficult question, don't go off the deep end.

8. This is a difficult question to deal with partly because of the dual purpose of the entire exercise.

9. He then turned to the difficult question as to whether land is capable of passing by donatio mortis causa.