Some one with both feet on the ground is a person with a good understanding of reality. 脚踏实地的人对于现实的理解很到位。
She has what is called "common sense." She may have dreams. 她懂得什么是所谓的常识。尽管她也可能做些美梦,
But she does not allow them to block her understanding of what is real. 但是她决不允许它们成为自己理解现实的障碍。
The opposite kind of person is one who has his "head in the clouds." 与此相反的一类人是“想入非非、心不在焉”( have one's head in the clouds )的人。
Someone with his head in the clouds is a person whose mind is not on what is happening in real life. 想入非非的人是指其想法不着眼于现实生活的人。