根据句意,用括号内所给单词的适当形式填空。
He said nothing but ____(simple) looked at me.
He went to Tibet to teach for two years although he was already in his (forty) .
He has such a heart full of ____ (sad) that it’s hard for him to cheer up.
Our dream is to ____ (creative) a whole new world for our children to live in freely.