如图所示,用嘴巴对着两张竖直放置的纸吹气,两张纸会__________,原因是_______________________.
向中间靠拢;中间空气流速大压强小
She has set a new record, that is, the sales of her latest book ___50 million.
A.have reached
B.has reached
C.are reaching
D.had reached
GIS的车辆路线模型可用于解决一个起始点、多个终点的货物运输中如何降低物流作业费用,可决定使用多少辆车,每辆车的路线等。( )