1.To study hard is easy for us.
2.应该只要是动词作主语就必须名词化或是动词词组吧.
3.Eating is necessary for us.
4.Blue is a beautiful color.
5.Ten is too many!
6.What I have done doesn't matter.
7.介词不能做主语.
8.那就最简单的名词作主语吧~Tim is a good boy.