已知：抛物线y=ax²+bx﹣3经过点A（7，﹣3），与x轴正半轴交于点B（m，0）、C（6m、0）两点，与y轴交于点D．

推动德国实现统一的根本动力是(    )

    Have you ever heard of Jinjiang Hotel? It is on our busiest street. It's the best place to live in if you travel here. The hotel is only 0.5 kilometer from the biggest supermarket and the subway.

    It has three kinds of rooms for different people to use. The first kind is standard room that is two beds with a bathroom. It offers you the air conditioner, the television and the telephone. Second is the single room that has only one bed. Though it has only one bed, you can enjoy yourself, for the bed is really comfortable and the environment is really good. The last one we call commercial room. That is served for businessmen. The commercial room has the best quality. It also provides 24-hour hot water. You can have free tea in the afternoon. Imagine how nice as you drink tea as talking about your business with your partners. If you want to eat something, please just call 123, the food will arrive in ten minutes.

    One great thing is that it is very safe here because we have a few strong guards working day and night, so I'm sure you will have a great time living here.