根据句意,写出括号内所给单词的适当形式。
小题1:Listening to music or visiting interesting places can make you forget your (sad).
小题2:As we all know China (successful) sent up her first man-made satellite in 1970.
小题3:It's very ( polite) that she left without any words.
小题4:The (angry) the mother is, the more scared the children become.