从方框内所给的单词中选出适当的单词并用其正确形式填空。

There are many kinds of tigers all over the world, and the    1   tiger is Northeast Tiger. Most Northeast Tigers live in the   2  of China, like Heilongjiang Province and Jilin Province. Because there are many   3     and mountains, the tigers usually like living there. Because there are fewer people   4   out and coming in. So the tigers are very free. They can  5     after each other, catch and eat some   6       animals, like rabbits and deer.

The Northeast Tigers are  7      from the ordinary tigers. For example, the Northeast Tigers can swim very well, but can't   8  the trees. The Northeast Tigers' hearing is the best, and no matter   9   low the sound is, they can hear it.

As the number of the tigers   10     smaller and smaller, we should protect the tigers as well as we can from now on.