It’s cold and dark outside, and your bed is so warm and comfortable. Going for a run seems like such a bad idea. But before you put your running shoes away, it might be worth giving that crazy idea a try.

According to The Huffington Post，an outdoor run in winter, instead of running on a treadmill (跑步机), burns more calories (卡路里) because the body is working hard to regulate (调节) its temperature. Besides, research shows that race times are faster in cold weather than in warmer temperatures—and quicker runs burn more calories. Similarly, cold weather also makes the heart work harder to distribute blood through the body, making that vital muscle even stronger.

Outdoor exercise also turns up your energy and rids you of the stress and depression that build up every day. The heat and humidity in summer can drag you down and tire you faster, but cold weather is refreshing. It adjusts you to your surroundings, making you feel energetic.

Of course, the threat of smog in some built­up areas is a further problem to winter exercise. Heart attacks, strokes and lung cancer are all dangers of running in smog. The combination (结合) of air pollution and exercise increases the potential problems. If you do choose to run outside on smoggy days, take a path in a park or residential area to avoid polluted air, and go early in the morning, before rush hour. But staying inside on smoggy days and waiting for the next clear day to run is best.

Have you ever considered all the English expressions that include words about clothes? Let’s have a look.

People wear pants to cover the lower part of their bodies. We sometimes say that people who are nervous have ants in their pants. Sometimes, people may get caught with their pants down, which means they are found doing something they should not be doing. And, in every family, one person takes control. Sometimes a wife tells her husband what to do. Then we say she wears the pants in the family.

Pants usually have pockets to hold things. Money that is likely to be spent quickly can burn a hole in your pocket. Sometimes you need a belt to hold up your pants. If you aren’t able to make ends meet and have less money than usual, you may have to tighten your belt.

I always praise people who can save their money and not spend too much. I really take my hat off to them. Yet, when it comes to my own money, I spend it at the drop of a hat, which means I immediately spend it.

Boots are a heavy or strong kind of shoes. People who are too big for their boots think they are more important than they really are. I dislike such people.

My father is a successful business man who runs a big computer company. He wears a suit and tie, and a shirt with sleeves that cover his arms. Some people who do not know him well think he is too serious and never shows his feelings openly. But I know that my father wears his heart on his sleeve.

Tips for the perfect selfie（自拍）

You can take a selfie with a hand-held digital camera or mobile phone and later share it on the Internet. So selfies have been especially popular over the years. 【小题1】 Love them or hate them, selfies show no sign of stopping.

After all, the selfie is the most important way to show off on holiday. Everyone has his own way to take the holiday selfies. How can you take the best holiday selfies? 【小题2】

Want to let everyone know how exciting your holiday food choices are? 【小题3】 You can also cut off a piece to show off what’s inside. But don’t have food hanging out of your mouth. Remember, food always looks best before being eaten.

Rock climbing, hiking, surfing, or skiing? 【小题4】 Just let the natural settings make people go “wow”. One commonly used gesture is spreading out an arm to show how thrilled you are. But remember that no one likes a sweaty selfie.

【小题5】 You can also try an optical illusion（视错觉）by making it look like you’re holding up the leaning tower of Pisa, touching the top of the Eiffel Tower, or picking the Sphinx’s nose.