Some questions you might ask about the research include:

Why is this research being done?
What is the purpose of the study?
Who is sponsoring the study?
Who has reviewed and approved this study?
Why does the research team think the treatment, drug, or medical device will work?

Some questions about your participation in the study include:

Where is the study site?
What kinds of therapies, procedures, and/or tests will I have during the trial?
Will they hurt? If so, for how long?
How will the tests in the study compare to tests I would have outside the study?
How long will the study last?
How often will I have to go to the study site?
Who will provide my medical care after the study ends?
Will I be able to take my regular medications during the trial?
What medications, procedures, or treatments must I avoid while in the study?
What are my responsibilities during the study?
Will I have to be in the hospital during the study?
Will the study researchers work with my doctor while I am in the study?
Can anyone find out that I am participating in a study?
Can I talk to other people in the study?
Will I be able to find out the results of the trial?

Questions about risks and benefits include:

How do the possible risks and benefits of the study compare with approved treatments for me?
What are the possible immediate and long-term side effects?