补全空缺短句，奖励100HY^^[cloze] But even in the rainy south, there are landscapes where water is surprisingly scarce. This vast area of southwest China, a size of France and Spain combined, is famous for its clusters of conical hills by giant upturned egg cartons separated by dry empty valleys. This is the karst, a limestone terrain has became__1__. Karst landscapes are often studied with rocky outcrops forcing local farmers to cultivate tiny fields. The people who live here are among the poorest in China.

In neighboring Yunnan Province, limestone rocks have taken over entirely. This is the famous Stone Forest, the product of __2__producing a maze of deep gullets of sharp-edged pinnacles. Limestone has a strange property that is dissolves in rain water. Of the many thousands of years, water has corroded its way deep into the heart of the bedrock itself

This__3__ is a famous tourist spot, receiving close to 2 million visitors each year The Chinese__4__. And many have been given fanciful names.__5__. But there is more to this landscape than meets the eyes.

China has literally thousands of mysterious caverns concealed __6__of karst. Much of this hidden world has never been seeing by human eyes, and it is only just now being exploded. [/cloze]