阅读下面短文，根据短文内容完成句子。

Dogs are the best pets of humans. They come in all sizes. Some dogs are as small as a football, and others are as tall as a desk. Dogs’ fur(毛) is different, too. It can be long and soft, or smooth and hard. People don’t mind the kind of fur, because all dogs are good to hug.

Dogs need to be taken care of. Short-haired dogs are the easiest to look after. But all dogs need a bath once in a while. Giving a dog a bath is a lot of fun. After you give a bath to your dog, it shakes the water off its body. Be careful, or you will get wet!

Dogs like to make their owners(主人) happy, so dogs are easy to train. They can follow simple orders.

Dogs are really amazing animals. Some dogs pull sleds(雪橇) across icy places. Some save people who fall into the river. Other dogs do tricks(表演绝技) in movies. A dog has even flown in a rocket(火箭) to space.

Why not keep a dog as a pet?

(1). Some dogs are ________ a football, and others are as tall as a desk.

(2). People don’t mind the kind of dogs’ fur, because ________.

(3). When you finish giving a bath to your dog, it ________ its body.

(4). Dogs like to make their owners happy, so dogs ________ to train.

(5). The writer advises people to ________ as a pet.