—Jenny，how did your math exam go?

—I thought I ________，but in fact I came in the top 10% in the class.

A．might have failed

B．couldn’t have failed

C．should have failed

D．mustn’t have failed

有人以韩非子的话“千丈之堤，以蝼蚁之穴溃；百尺之室，以突隙之烟焚”来形容党员干部腐败对党和国家的危害。这说明（）

①事物变化发展的实质是引起质变的量变

②事物的质变是由渐进的量变引起的

③事物的量变必然引起质变

④事物的不显著的量变可以向质变转化

A.①②

B.②③

C.②④

D.③④