(2013·济南市一模)—I will have to think about it again.

—If you ________， you may lose the opportunity to compete altogether.

A．hesitate

B．wonder

C．continue

D．fail

在有连续调光、瞬时启动、开关频繁要求或限制电磁波干扰的场所，可选用白炽灯或荧光灯光源。()