There’s an old saying: “Laughter is the best medicine,” and modern research certainly shows that laughing is good for you. When you have a good laugh, you exercise your muscles (肌肉), strengthen your heart and balance your body chemistry. However, these are the results of having a laugh, not the explanations (解释) of why we do it.

Until recently, scientists believed that laughter was a human behavior only. They argued that people find jokes funny because we can put ourselves in another person’s shoes, and that animals can’t do that. People don’t all have the same sense of humor. Sometimes there isn’t any joke; but we laugh because the people around us are laughing. How long and how loud we would laugh are also shared. We just go on following the example with one another until the laughter fades away (消失).

Many pet owners insist that animals have a sense of humor, too. For example, pet dogs often run away with a slipper (拖鞋), inviting their owners to run after them. Dogs even seem to smile when their owners join in the game. As the game continues, our pets make noises that are very like laughter. You can compare this behavior to the laughter of a baby, waits for the adult to pick it up and throws it down again.

Perhaps laughter is just a sign that we are having fun. Fun, like laughter, is the best when we share it with friends.

Beating the Winter Blues

Does your mood change with the seasons?

Some people find that when the temperature goes down, so do their spirits. Those people sometimes feel sad for no reason. They eat more and put on weight. They have trouble sleeping. They can’t think clearly. This is the winter blues. 【小题1】.

Get out in the sun. Some experts say that the winter blues happens because we get less sunlight in the winter than we do in other seasons. They say that the decrease（减少） in sunlight can make us feel sad. 【小题2】.

Get some exercise. Taking a walk or doing some exercise will make chemicals（化学物质called endorphins in your body. Endorphins are natural “feel good” chemicals.

【小题3】. Avoid having too much sugar. If you prefer sweet food, like cookies or candy, it may be a sign that you need more protein, chicken, or fish.

Reduce stress. Cut back if you have too many things to do? Make sure you have some quiet time to yourself

【小题4】. Don’t be so busy that you get run down.

Get help. If you feel sad all the time and the feeling won’t go away, you may have a bigger problem than the winter blues. 【小题5】, or get help from a doctor.

“Did you go skating a lot last year?” I asked. Jen shook her head and looked at me. Finally she said, “On Thanksgiving, Mom and I always went to visit some friends who lived on a farm. I especially loved seeing their big turkeys.”

Until then, I didn’t think about how Jen felt. She had a new stepfather (继父) and stepbrother, and had a new town and home, too. Jen and her mom used to live near a lake where Dad and I went every summer, and she had to move up north with us. She had more changes than me.

Jen seemed sad, so I was busy thinking of some ways to cheer her up on Thanksgiving. I told her my plan and she was excited. First we made a huge snowball, and then a small snowball. Then we built a wall behind the big snowball as a tail. Jen mixed some food coloring with water, saying, “We can spray (喷) colors on the tail.” Our snow turkey had a red, blue, green, and yellow tail. We were so busy that we didn’t notice our parents come outside. Dad found a hat for the snow turkey, and Mom wrapped her scarf around its neck.

“Thanks for cheering Jen up,” Mom said. “You’re a good brother, and you always come up with great ideas.’’ A happy feeling spread through me. I began to understand how much she cared about everyone in our new family.