Marseans:
Sounds like you're trying to create a form in Word. If you search the Help
for "form" you'll get all the answers you need.
In general, you open the Forms toolbar and add form fields to your document
wherever you need them. Then you protect the form (Tools > Protect Document >
Forms -- or click the Protect Form button on the Forms toolbar) and the users
can only access the form fields.
Alternately, you could put your questions and the answer paragraphs in
separate sections. When you click Tools > Protect > Document > Forms, you can
also click the Sections button. This lets you protect ("lock") whichever
sections you want to. so your questions, being in sections you protect, would
not be accessible, but your answers, in unprotected sections, could be freely
edited by your users.
Bear