请教2000年1月32题

questionmark

32. Female sea turtles, before laying her eggs, swim as much as 2,000 kilometers to return to the beaches where they themselves were hatched.

答案是A没错，但有一点疑问，就是那个as much as 为什么不用as many as，后面的kilometers可数啊？谢谢。

questionmark

as much as 修饰swim我不太认可，但是说2000 kilometers不是复数又是什么呢？那个例子我也不太明白为什么要用is