下列不属于黄土高原水土流失的自然原因的是（　　）

In the earthquake, parents were willing to do         they could        their children.

决定人的有耳垂与无耳垂性状的是（    ）

The clean-up operation at the bullet train crash site in east China’s Zhejiang province has been completed. Meantime, trains have resumed services on the railway ______ the accident occurred.

On the rescue scene of the copper mine in Chile, the crowd cheered _________ a miner was safely brought to the surface.