1 . Are you diligently exercising but seeing no result around your midsection（上腹部）? It's not just you. Two new studies may explain why many people who begin exercise programs often lose little to no weight in the long run.
In the first study, published in the online science journal PLoS One, researchers compared the daily energy consumption of Westerners and the Hadza, a population of hunter-gatherers living in northern Tanzania. Many believe modern Westerners burn fewer calories than in the past because their lives have become more sedentary（久坐的）. The Hadza, who are generally very thin, hunt and look for food without modern tools such as vehicles or guns. Men walk about seven miles each day, while women walk about half that.
What was surprising was that although the Hadza seem to be more active, the researchers found little difference in calories burned between the Hadza and the Westerners.
The second study, published in Obesity Reviews, analyzed the effect of exercise interventions on body composition. The researchers found that—contrary to popular belief—when people exercise but keep their energy intake constant, their resting metabolic（新陈代谢的）rate actually goes down. Exercises who ate more calories than they usually do did burn more fat than predicted, but some overate and negated the effects of their hard work.
These studies suggest two things: exercise programs may not lead to as much calories burn as you would think, and many people start eating more when they exercise, and they may eat too much.
Bottom line, if you start exercising to lose weight, you won't succeed with the mentality of “I can eat anything because I'll burn it off later.” You will have better results if you choose a healthy diet of whole grains, fruits and vegetables, lean proteins and healthy fats while exercising. Although these two studies show that diet may be more important than exercise for weight loss, don't discount the other benefits of exercise, including decreased stress and anxiety, improved mood and reduced risk of cardiovascular（心血管的）disease, diabetes and some cancers.
1. What dose the two studies show in common?| A．Exercises are of great benefit. |
| B．Exercises make people eat too much. |
| C．Dieting may be not so helpful for weight loss. |
| D．Exercises do not necessarily lead to weight loss. |
| A．Improved. | B．Doubled. |
| C．Denied. | D．Aroused. |
| A．a science magazine | B．a book review |
| C．a health guideline | D．a news report |
2 . Fire ants dig tunnels efficiently by only a small percentage of the group doing most of the work. Free-loaders just sit around while their hard-working colleagues get things done. But might freeloaders actually be necessary for society to function efficiently? The answer could be yes.
Fire ants are highly social organisms. So, Goldman, a physicist at Georgia Tech, and his colleagues wanted to know how individual ants knew what to do without a central leader issuing orders. To find out, Goldman's team labeled individual fire ants with paint and then watched them dig their narrow tunnels —barely wide enough for two workers. Turns out, just 30 percent of the ants did 70 percent of the labor. “I was surprised that we ended up with so few workers actually doing the work at any one time. ” A quarter of the ants never even entered the tunnel. Others crawled inside, but left without digging single grain of dirt. These idling behaviors ensured the tunnels did not get clogged with insect traffic, which would make the construction process stop.
And when the scientists removed the five hardest working ants from the colony, others immediately jumped in to compensate (补偿) — with no reduction in the group's productivity. It seems that it doesn’t matter which ants are working or freeloading at a given time, as long as there is some division of labor to keep the tunnels flowing smoothly. The findings are in the journal Science.
The study could have implications for robotics. Imagine groups of robots sent to search rubble (碎石) for disaster survivors. Or nanobots (纳米机器人) coursing through our bodies to diagnose illness and deliver targeted medical treatment. Such robot groups will need to avoid getting jammed up in tight spaces. It might be necessary to program them so some just sit back and watch their comrades work.
1. How do fire ants get the work done when digging tunnels?| A．Only the leaders do most of the work. |
| B．They all work under the order of one leader. |
| C．They all cooperate together to do the work efficiently. |
| D．Individual fire ants know their tasks and work efficiently. |
| A．crowded | B．transported |
| C．organized | D．covered |
| A．The ants will have no idea what to do. |
| B．Other ants will take their place and do the work. |
| C．The tunnels will get blocked and the work will stop. |
| D．The leader will compensate them and give them food as the reward. |
| A．fire ants are the most diligent insects. |
| B．scientists may diagnose illness more easily. |
| C．people may feel happy when they watch their colleagues do nothing. |
| D．scientists can deal with robotics better when coming to specific programs. |
