题目

我国喜马拉雅山区发现了大量的古海洋生物化石，这证明这里曾经是（ ）A.海洋 B.森林 C.火山 D.河流 答案：【答案】A【解析】喜马拉雅山位于印度洋板块和亚欧板块的碰撞挤压处，在喜马拉雅山区发现了大量的古海洋生物化石，证明了喜马拉雅山处曾经是海洋，后来由于地壳的抬升形成了山脉，故选A。All these gifts must be mailed immediately _____ in time for Christmas. [     ]A. in order to have received B. in order to receiveC. so as to be received D. so as to be receiving