31. We haven’t seen each other from we left school.

               A                 B               C                  D

32. Although Nam worked very hard, but he didn’t pass the final exam.

          A                                        B                C          D

33. Dinosaurs became extinct millions of years ago because of the earth's climate changed drastically.

                              A                                                  B             C                                        D

34. Although taking a taxi, Bill arrived  late for the concert.

     A                                     B                           C                                   D

35.5. She worked  too hard   that   she became ill.

       A          B      C                                               D