It's fun to do sth.和It's fun doing sth.怎么用

有例句，还有一道题
There will be________ in the south of the country.
A rain B rainy C raining D rains
选什么，为什么不选其它的
谢谢
除了这道题,还有啊,It's fun to do sth.和It's fun doing sth.怎么用,回答啊

It's fun to do sth.和It's fun doing sth.怎么用 It’s fun to do the impossible.译成中文是? it's fun 还是it 's funny It's fun to go for an outing on such a fine day. 怎么改感叹句?fun是名词吗 ｛It's better to it's a fun place中的fun是形容词还是名词？ .....it's easy to understand 还是....it's easy to understand it IT'S UP TO YOU it's up to u !是什么意思？ It's up to you!