Have you ever heard of friendships among animals？At a zoo in Germany，（1）

an

an

unusual friendship developed between a cat and a bear.
    No one is quite sure how the friendship first began.One day，some（2）

workers

workers

（worker） in the zoo noticed a black cat was in the bear's cage，and the two animals were playing together peacefully.They were surprised how well the small cat seemed to get（3）

along

along

with the large bear.The bear keeper allowed the cat（4）

to stay

to stay

（stay） with the bear.And later the pair and their unusual friendship（5）

became

became

（become）a hot topic at the zoo.
    After several years，a new cage（6）

was built

was built

（build） for the bear.However，the cat was still in the same cage，so it walked around（7）

angrily

angrily

（angry） and cried to be with the bear.The bear keeper finally took pity on it（8）

and

and

let it stay with the bear.The cat and the bear got（9）

closer

closer

（close） than before.They often sat together and shared meals in the sun.
    Sometimes it may be natural for animals（10）

to have

to have

（have）their own ideas about who would make a good friend.These may surprise humans，who usually expect animals to form relationships with others of the same species.