下列因素不利于聚落形成和发展的是（　　）

A．丰富的资源

B．便利的交通

C．险峻的高山

D．平坦的地形

Such an inspiring speech ________ at the graduation ceremony that every one of us was deeply moved and strongly encouraged.

A．did he make

B．he made

C．had he made

D．he had made