用方框中所给单词的适当形式填空，使句子通顺，正确。每词限一次。

thin  twelve  cost  south  develop

Mr. Green lives on the __________ floor of the building.
After exercising for a few months, she is a little           than before.
How much does it          to fly to Shanghai from Fuzhou?
Many foreigners are surprised at the rapid _______________ of China.
It rained heavily in the          of Zhejiang Province last week.