some systems, you may, apparently quite randomly, start to see "black
bars" over test question answers. We believe that this happens
to well less than 2% of users.
appears to be due to a deep bug in certain MS-Windows video drivers
or related subsystems.
this happens to you, we suggest running the program in 'full screen
mode.' Full screen mode works by a completely different drawing technology
and therefore will not have this problem.
enter full-screen mode, click on the button as shown below.
for your Understanding, and Good Luck on your test!