---Can you ask him to give up the foolish idea?

---_____ no point in doing so—he’ll never change his mind.

A．It is

B．It has

C．There is

D．There has

将物体放在三个互相（）的投影面上，使物体上的主要平面平行一投影面，然后向三个投影面作正投影，得到的三个图形称为三视图。

A、平行

B、交叉

C、垂直

D、倾斜