阅读下面短文，写出括号中所给动词的正确形式，使短文意思完整。

     Mr. Johnson had a factory. He once saw on TV that animals could be taught    1    (do) some work for

people if they    2    (give) to eat. He loved the idea. He thought it would be good to have a dog look after

his house and an elephant do some heavy jobs in his factory. He bought a dog and an elephant in the market

and    3    (decide) to teach them to do some work for him. Of course, he also bought a lot of food for them.

Several months later, the dog and the elephant    4    (become) fatter and fatter, but they couldn't do any

work for him. At last, Mr. Johnson had to    5    (give) up.

1.______ 2.______ 3.______ 4.______ 5.______