为什么大熊猫是黑白相间的？科学家终于揭晓了谜底。请看本报昨日的报道：

    The unique coloration of the giant panda that is loved by many people has long been a mystery to scientists. But now a joint research team believes they have solved the mystery, once and for all.

    The black and white patches on the giant panda mainly have two functions — camouflage and communication, the joint research team from University of California, Davis, and California State University, Long Beach explains.

    报道中的once and for all就是“一劳永逸地、彻底

    地”，例如：

    I must tell you once and for all that I won’t marry you.

    我必须断然告诉你，我不会嫁给你。