Could you elaborate further?
Could you give me an example?
Could you illustrate what you mean?
How could we check on that?
How could we find out if that is true?
How could we verify or test that?
Could you be more specific?
Could you give me more details?
Could you be more exact?
How does that relate to the problem?
How does that bear on the question?
How does that help us with the issue?
What factors make this a difficult problem?
What are some of the complexities of this question?
What are some of the difficulties we need to deal with?
Do we need to look at this from another perspective?
Do we need to consider another point of view?
Do we need to look at this in other ways?
Does all this make sense together?
Does your first paragraph fit in with your last?
Does what you say follow from the evidence?
Is this the most important problem to consider?
Is this the central idea to focus on?
Which of these facts are most important?
Do I have any vested interest in this issue?
Am I sympathetically representing the viewpoints of others?