_________ there any grass and trees in front of your house—- No, but behind the house ________ some trees.

(2014·烟台市第二次诊断)Vitamin D helps our bodies make a special chemical，and this special chemical，________，affects our brains，making us feel happy

Jane and Joan have been friends for fifty years.— No wonder they have such a lot in ______.

Nowadays many parents complain that they can’t ______ their children’s different kinds of expenses and that they don’t know how to make themselves understood.

During lunchtime, we always have fun_____ each other.