A standard one. Replacement during the first year if all rules for proper use have been followed.
有一个原则,如果在一年内符合各种使用规定,就可更换。
This immense chasm has been formed by an underground stream which has tunneled a course through a flaw in the rocks.
这个深邃的洞穴是由一条地下暗泉冲刷岩石中的缝隙并使之慢慢变大而形成的。