听力原文：When you have a dog it is necessary to care for it very carefully. In return you

The most important part of dog-care is cleanliness. Not only does the dog have to be kept clean, but his environment should also be clean. The bed he sleeps in can be made with anything like a rug or a dog mattress.

Proper feeding is also important for your dog's health. A dog should be fed in the same place and on a regular schedule. If your dog refuses to eat, don't force him. Remove his food and don't feed him again until his next regular feeding. Food should never be left before a dog for more than 30 minutes.

One important thing that many dog owners forget is exercise for the dog. Vigorous exercise helps build strength and keeps the dog healthy. A regular walk at a fixed time of the day is enough to help a smaller dog live a healthier end happier life. Large dogs, though, require a run in an open fid&

There are other things that are also important for a dog's health — things like bathing, care of the teeth and nails, keeping them away from insects as much as possible. But if you observe the three main points covered above, your dog will give you a great amount of pleasure.

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A．Until he eats it.

B．All day.

C．At lease 30 minutes.

D．No more than 30 minutes.