题目

—Do you know if we will be free this Saturday? —I don't know, either. ________ the teacher? A．Why not to ask    B．Why not ask C．Why do not ask    D．Why don't ask   答案：B句型 Why not...？＝Why don't you...？用于提出建议，后接动词原形。  对称现象无处不在，请你观察下面的四个图形，它们体现了中华民族的传统文化，其中，可以看作是轴对称图形的有（　　）A．1个B．2个C．3个D．4个