Are you saying that cell widths increase as text is added to cells,
and you want to prevent that from happening? Then you should do
the following: On the Table menu, click Table Properties. Click the
Table tab. Click Options. Clear the "Automatically resize to fit
contents" check box and click OK twice.
Note that you can also fix the row heights of your table, so that the
table doesn't become "too large" to fit your document layout: On the
Table menu, click Table Properties. Click the Row tab. You can use the
Previous row and Next row buttons to select the various rows of the
table. Select Specify height, choose a unit of measurement and type
the desired value (it may require some trial and error to find the
proper one).