—I think she can't believe it.

    Like humans, dogs donate blood too, and not every dog can donate blood. The dogs are screened(检查) for health first. Dogs must have the correct blood type, weigh at least 55 pounds and be younger than 8 years old. They may donate three or four pints(品脱) a year, which can help animals that are suffering from illnesses like cancer or an accident like being hit by a car. One pint can save up to three dogs.

    Owners volunteer their pets for the short procedure (程序), which requires no sedative, a kind of medicine given to calm him or her down. It's the dog that finally chooses to lie still and give. If the dogs want to get up and leave, they can.

    Sandy Lucas brought her 7-year-old black German shepherd, Rains, to the bloodmobile(流动血站) when it was parked at her small village. Sandy said she wouldn't have troubled herself with highway traffic and city parking problems to take the dog to Penn Vet's animal hospital in downtown Philadelphia, which is twice as far as her home. But the bloodmobile made it easy to find out if Rains could donate. "I was very, very excited that she had the right blood that was needed to help another dog out," said Sandy. "We'll surely do it again."

    There is little doubt that house cats first developed naturally from ancient wild cats. The cleverest relative is the American wild cat which still lives in Africa today. This is understandable because the first house cats came from Africa.

    Cats first started to live around people in Egypt about 6,000 ~ 7,000 years ago. From Egypt, cats started to move around the world. At about the same time, Egyptians began storing grain(谷物) in buildings. Scientists used to believe that people tamed cats to catch mice and protect the grain. However, cats don't like to be told what to do! Now, scientists believed that eats followed the mice and learned to accept people. Finally, some of the cats began to grow comfortably around people. These were smaller cats that needed protection. As these cats and people got used to each other, they moved in together.  Around 5,000 years ago, eats started to live with people.

    Soon cats were in Greece, then the Middle East and China. They moved along Egyptian business roads keeping away mice and keeping people around them. After the Romans came to Egypt, they also accepted the cats and brought them to Europe. These cats likely bred(繁殖) with other cats to form the many kinds of house cats we have today.

    Cats are relatively recent house animals. House cats still have a lot in common with their wild relatives. Cats sleep a lot to save energy just like wild cats. They often get food at night as well. House cats are generally peaceful and friendly, but be careful! If a cat feels it is in danger, it will fight back—just like a wild cat.