据句意及单词首字母完成句子。

1. He is h       , so he will pass the exam.

2. Students are s         to keep the classroom clean.

3. She didn't r            home until 11:00. 

4. L        , he found his book that he had lost.

5. To my s           , Tom did come to the party.

英国科学家波普尔说：“如果我们过于爽快的承认失败，就可能使自己发掘不了我们多么接近正确。”这句话告诉我们（）

①辩证否定是事物之间的相互否定②事物发展是前进性与曲折性的统一

③矛盾双方在一定条件下相互转化④真理是主观性和相对性的辩证统一

A.①③

B.①④

C.②③

D.③④