题目

For quite        students, their teacher’s advice is more important than      of their parents. A．few; one        B．a few; that          C．a little; some          D．a lot; many 答案：B19．向量$\overrightarrow{a}$、$\overrightarrow{b}$的坐标分别是（2，-3），（5，-4），求$\overrightarrow{a}$•$\overrightarrow{b}$．