Find and correct the mistake in each sentence

IV.  Find and correct the mistake in each sentence.

      33. He said that they will have to set off soon after midnight.                                     

                           A            B                 C                 D

      34. When he lived in Japan, he didn’t used to eat food with forks, but with chopsticks.   

            A                     B          C          D

      35. He thinks that geometry is not as difficult than arithmetic.                           

                     A                             B                C        D