If you are an energetic person with p views as to the right way of doing things, you find yourself________ under pressures.

A．variably

B．invariably

C．invaluably

D．invalidly

跨区域灭火救援行动的特点是：情况复杂，任务艰巨；（）；参战力量多，指挥协调难；后勤保障任务重、难度大。

A.路途远、车行困难

B.异地作战，不利因素多

C.水源少、易使火势蔓延

D.通信距离大、联络困难