begin,  unhappy，walk ,While, rain , grow , useful ,get

 
One day, a little boy and his father went out after dinner, While they were _ in the park ,it suddenly__to rain. They didn’t have raincoats, so they __very wet soon. The little boy felt__.
they were walking home in the rain, the boy thought of something. Then he turned to his father and asked, “Why does it ___,Daddy? Do you think it is nice?”
“ It isn’t nice .But it’s very _” Answered his father. “ It rains to make crops and vegetables  grow for us, and to make grass (草)_ _ for cows. ”
The boy thought about this for a few seconds, and then he said, “ Then ,why does it rain on the road too, Daddy?”