北极熊可能非常危险。

___Polar ___bears can be very dangerous.

为北极熊创造真实的生活环境很困难。

It's difficult to create real-life conditions for ___polar ___bears.

北极熊利用其白色皮毛在雪中伪装。

A ___polar ___bear uses its white fur for camouflage in the snow.