请教大家一道题

The black leopard is very dark that its spots are   difficult   to see.

请问各位答案为什么是is very 呢

谢谢

这种改错题在考试不易看出来，是属于so...that..结构的题型。正确的应该是：

The black leopard is so dark that its spots are diffculty to see.