依次填入下列横线处的词语，最恰当的一项是(　　)对于黄河来说，晋陕峡谷好像是铜墙铁壁，滚滚流淌的黄河水，一进入这道　　　在晋陕之间的天堑，就变得暴躁起来，若一队浩荡奔来的铁骑，在一道道关隘前，越战越勇，　　　越陷越深。在岩石与激流的　　　中，碰撞出　　　的气势，又绘制出一幅幅令人心荡神驰的美景。

It was at the airport _____ was completed last year _____ he worked as a volunteer helping foreigners in need of translation service.

Some people don’t like living in noisy cities, so they move _________.

When shall we restart our business— Not until we ourplan

. ______ the ancient Egyptians built the pyramids puzzled people for centuries.