《天朝田亩制度》具有绝对平均主义性质，主要因为它规定

    Hello! I'm Scott. The old woman on the sofa is my grandmother. She is 78 years old, but she is very healthy.

    Every morning, she gets up at 6:00 o'clock. And then she does some exercise for half an hour. For breakfast, she usually has a cup of milk, some bread and an egg. After breakfast, she always goes to the art club. She teaches the people to draw pictures. In the afternoon, she often goes to the park (公园) with her friends. She likes dancing very much. She has dinner with us at 6:30 in the afternoon. After that, she likes to go for a walk with my grandfather. She goes to bed at 9 o'clock.

下面平行四边形的面积____．

​，只能列式为：7-3=4。