Please solve this exercise ???????

Dear Student,
Incorrect= Correct
 (1)on 1825, developed a special script for the blind. It (On=In)
(2)has known as a Braille script. (has=is)
 (3)with raised dots on thick paper(with=by)
(4) might read these  (might=can)
(5)his fingers lightly (his=Their)
(6)to them, across the page. (to=on)
(7) in almost  (in=on)
(8)is available.(is=are)

Regards