Every parent has only one child and every grandparent has only one grand-child.
Every parent has only one child and every grandparent has only one grand-child.
一个家庭只有一个孩子，而祖父母只有一个孙子。
Every parent has only one child and every grandparent has only one grand-child.
一个家庭只有一个孩子，而祖父母只有一个孙子。