根据句意和汉语注释，写出单词的正确形式。
小题1:_______ (污染) air does harm to our health. It’s necessary to keep the air fresh and clean.
小题2:Our success was far _______ (超过) what we thought possible.
小题3:This kind of disease _______ (传播) so quickly that it drew the government’s attention.
小题4:The man kept remembering English words every day until he was in his _______ (四十).
