题目

 Could you tell me           a meeting in Guangzhou next week?    A. if there was going to be              B. if there is going to be    C. whether is there going to be        D. whether there is going to have 答案：B对于静止在水平桌面上的书来说，下列各组力中属于平衡力的一组是（　　）A．书的重力和书对桌面的压力B．书的重力和桌面对书的支持力C．书对桌面的压力和桌面对书的支持力D．书的重力和桌子的重力