Setting a cell size or row height in Word XP table

I have a table which is one column wide but has eight rows. The first and subsequent odd rows contain a question such as ‘Comment of Line Manager’. The second and subsequent even rows are for comment to be typed into.

However we do not want the these cells to grow; we need only a few comments to be made. If we set the row to be ‘Exactly’ a specific length and the user continues to type away then the text goes below (or behind) the next row. It does not stop the user typing.

How can we stop the user trying to use more than the allowed space?