People may easily ignore（忽视） that we are living in a world full of different c __, such as red, blue, green, black, v_____and so on. We can never tell how many kinds of them there are. But we all know that colors are very important in people's e_____ life. The sky is blue and white. The trees are green and yellow. We can even say that s______ is freshing green, summer is hot blue, autumn is golden yellow and winter is c______ white. I___ one day all the colors disappear，what will it be to live in this world. We feel b______. We can't even tell the d________ between the sky and land, between trees and houses. The world is c_______. And we can't live w________ colors.