根据句意，在答题卡标有题号的横线上，写出括号内所给单词的适当形式。
During the Olympics, the man passed his own ___________ (forty) birthday.
The fruit and vegetables are good for the health ___________ (develop) of children.
The girl didn’t speak clearly enough to make ___________ (she) understood.
I think maybe this is the ___________ (silly) mistake I have ever seen.