题目

物体作平抛运动，速度v，加速度a，水平位移x，竖直位移y，这些物理量随时间t的变化情况是（A）v与t成正比            （B）a随t逐渐增大          （C）比值y/x与t成正比     （D）比值y/x与t2成正比  答案：C解析:略  7. Peter can't speak Chinese and can't write it, _____. So Chinese is Greek to him. A. too                      B. also                    C. neither                 D. Either