题目内容：

You’re sitting on the sofa, and there’s your dog, right at your feet. You stand up? He stands up. But then you head to the bathroom, and guess who comes with? Why, your dog, of course. But why? Why does your dog follow you like a shadow, no matter where you go?

Ever get the feeling you're being followed? As for why your companion follows you everywhere you go, read on !

“When dogs follow their owners, there can be several scientific explanations, depending on the dog and the individual situation,”according to Mary Burch, Ph.D., an animal behaviorist(行为学家).

These explanations include:

Positive reinforcement(正面强化): When your dog follows you, good things happen. Think dog food, a hot bath and taking a walk around the neighborhood. Your dog’s no dummy. And one of his many talents is learning from experience, that is “reinforcement.”

Natural instinct(本能) to be part of a pack: In fact, a study out of Princeton University that was published in the journal, Science Advances, shows that your dog’s drive (驱动力)to follow you around (as well as watch you attentively and seek physical contact (身体接触) from you) lies in his genes(基因).

Feel good chemicals(化学物质): Your presence causes your dog’s brain to release “feel good” chemicals, Dr. Primm explains, citing this study. Considering how much we as humans enjoy those feel-good chemicals, it’s no surprise your dog likes them too—and will follow you around to get some!

Sense of responsibility : As you move about your home, your dog might feel that you are patrolling your territory (巡视领地) and take on the duty to assist you.

1.What is the passage mainly about?

A. Explanations for some dog behaviors.

B. Some natural instincts of the dogs.

C. The reasons why dogs follow you.

D. Dogs are good friends of human.

2.How does the author introduce the topic?

A. By listing numbers.

B. By giving examples.

C. By telling a story.

D. By making a survey.

3.What does the underlined word “dummy” mean in Para 5?

A. cute.    B. considerate.

C. stupid.    D. lovely.

4.Why does the dog like to be part of a pack?

A. This kind of behaviour is reinforced.

B. Dog’s brain releases chemicals.

C. Dogs have sense of responsibility.

D. It is passed from elder generations.