The manager is still on _______ vacation, so I will be in _______ charge of the meeting today.

A．/; the

B．the; /

C．/; /

D．a; the

读等高线地形图，选择正确说法（　　）

A．图中C---D是缓坡

B．图中A---D是山谷

C．图中B---D是山脊

D．图中C点与E点的相对高度是300米