根据句意,在答卷标有题号的横线上,写出括号内所给单词的适当形式。
They are planning when and where to celebrate his grandfather’s _____(ninety) birthday.
‘Nanjing! Nanjing!’ is a film full of _____(sad). All of us felt depressed after seeing it.
The weather in the north is much _________(dry) than that in the south.
The world _______(it) is changing all the time.