用所给动词的适当形式填空。

1. There ______ (use) to be animals in the forests.

2. I don't think no zoos are______ (suit) for animals to live in.

3. We can see that the animals are         _  (keep) in tiny cages and can hardly move at all.

4. I have never        __  (see) such a big elephant like that.

5. I urge all of your readers               (visit) our wonderful zoo soon.

一本练习本7角钱，小明拿3元钱，要买5本，还差多少钱？