关于重力和重心的理解，下列说法正确的是（） A.重心就是物体上最重的点 B.重心一定

The Most Popular Pets in the world
What are the most popular pets in the world? Cats and dogs!
小题1:___.This is around half of the country’s population(人口).About 60% of American families celebrate（庆祝） their pets’ birthday.
Cats and dogs are also good topics for small talks---“ What a lovely dog! What’s his name?” 小题2:__
People think dogs are loyal（忠诚的） animals. They help do lots of jobs like hunting(打猎 ) and guarding(守卫 ). 小题3:_______. In 1957, Russia put a dog called Laika into space.
Cats catch mice. They are not as loyal as dogs, but they can make people happy.
Today, cats and dogs are both people’s good friends.  小题4:___. The most famous ones are Garfield and Snoopy. Garfield is a lazy fat cat. He likes eating and sleeping all the time. He is smart, too. He can write some letters and tell time sometimes, although he often repeats that he can’t. He is often mad at his master who can understand him well. Snoopy is a kind small dog. 小题5:______ . He likes to write stories and make his friends feel better.

They are really tiring. They are in the most popular cartoons He is quiet and he has many good friends. People easily become friends because of pets They even went into space earlier than people Also, there are many other different types of pets. In the USA, there are more than 100 million cats and dogs.