【推荐1】At some point, all baby birds have to leave the nest. But songbirds often push their young out long before it's actually time for them to spread their wings and fly, research from the University of Illinois finds.

“From what we can tell, instead of physically pushing their young out, bird parents do this by decreasing the amount of food they give them to force them out through hunger, and by communicating with them directly to encourage them to leave,” says lead author Todd Jones, a doctoral student in the Department of Natural Resources and Environmental Sciences at the University of Illinois.

The study shows that the young birds who were forced to leave early were less likely to survive than those that stayed in the nest. “Birds that leave the nest at a younger age have less developed wings, and as a result often die before adulthood. Those that stay home longer can fly away when they finally leave and are more likely to survive,” says Jones.

Then why would songbirds push out their babies before they can fly? “Rather than leaving all their eggs (or in this case young birds) in one basket, bird parents can get their young to leave the nest earlier and spatially separate all the young birds so that the probability of all their young being eaten becomes nearly zero,” Jones says.

For the young birds that want to stick around, being forced out of their nest might seem like a cruel parental tactic. With no other choices, the little birds have to begin making their own way in the world, with the hope that one day they'll do the same thing to their own young.

“Our study suggests this tactic finally improves parental fitness and is likely passed on from generation to generation, Jones says. “Birds face many challenges in our changing world, and it is important that we understand tactics, such as the one mentioned in our study, that birds may use to respond to such challenges so that we may protect these birds.”

1. What would songbirds do to get their young out of the nest?

A．Show no care to them.	B．Physically push them out.
C．Attract them out with songs.	D．Stop giving them enough food.

2. What can we learn about the young birds forced out of the nest?

A．They will try to find another nest.	B．They will learn to fly very quickly.
C．They will be willing to come back.	D．They will have less chance of survival.

3. Why do songbirds make their young leave before they are ready?

A．To lead an easy life themselves.	B．To make space for their reproduction.
C．To avoid losing all their young to enemies.	D．To encourage independence in their young.

4. What does the underlined phrase "the same thing" in paragraph 5 refer to?

A．Protecting young birds from dangers.

B．Forcing young birds out of the nest early.

C．Punishing young birds if they do something wrong.

D．Letting young birds stay in the nest until they grow up.

【推荐2】Scientists have long wondered how baleen whales can sing while holding their breath Experts already knew that baleen whales have a special larynx (喉) that enables them to sing. But they didn’t know exactly how they produced sound.

“You can’t just go down a baleen whale and see what they’re doing when they’re singing,” jokingly says Joy Reidenberg, a professor who studies whales. Above all, dead whales are usually destroyed by natural chemical processes too quickly to collect living tissue samples.

Three young whales which happened to approach the shore close to his lab enabled lead author Coen Elenans to simulate (模拟) what happens when the animals produce sound. They'd assumed that the inner edges of the whales’ vocal cords (声带) rub together to make sound, but the experiment revealed the vocal cords rub against a fat part at the back of the larynx.

Reidenberg thinks the sample size of the study just three animals is too small for such a generalization, and that scientists need to examine more samples, Heidi Pearson, professor of marine biology at University of Alaska Southeast, agrees, She’d like to see a different family of whales examined for comparison, as the three individuals studied were all young whales.

Elemans says he wants to study adult males, which are known for their singing. But the experts acknowledge the challenge in doing so, “Just getting those samples is n great achievement in its own right,” says Pearson.

The researchers did another study. They used 3-D computer simulations to recreate what happens when the whales’ larynx muscles are activated. They discovered these structures cannot produce sound at higher frequencies than 300 hertz (Hz), or below depths of about 330 feet.

“Unfortunately, that depth and frequency range overlap (重叠) almost perfectly with what humans make,” says Elemans, meaning they may struggle to compete with noise generated by ships, which send out sounds between 30 and 300 Hz.

“That’s why the study emphasizes an urgent need to decrease noise pollution by limiting shipping traffic, setting up slow zones, protecting areas with lots of vocalizing whales, making ships quieter,” says Reidenberg, “and using real-time data in conservation plans.”

1. What is the challenge of studying how baleen whales produce sound?

A．Dealing with dead whales’ tissues.	B．Getting suitable samples for study.
C．Simulating the whales’ vocal cords.	D．Analyzing 3-D computer simulations.

2. What is Heidi Pearson’s attitude towards the first study?

A．Doubtful.

B．Admiring.

C．Unclear.

D．Optimistic.

3. What can we infer from the second study?

A．Ships on the sea frequently run into baleen whales.

B．Baleen whales enjoy competing with mankind on sound.

C．Baleen whales’ vocal cords rub together to make sound.

D．Human-made sounds affect baleen whales’ producing sound.

4. What does Joy Reidenberg suggest doing at last?

A．Ships are supposed to make way for vocalizing whales.

B．More data should be collected to analyze noise pollution.

C．Making plans to do further search on baleen whales’ habitat.

D．Taking measures to cut noise pollution for whale conservation.

【推荐1】As overweight is becoming a great concern, it is a good time to look at some common beliefs, myths（谬见）and the facts. This could be used as a guide to those who need it.

Fat Loss Exercise Myth No. 1—In order to get the best out of your weight loss program, you would need to take your cardio（有氧运动）the first thing in the morning.

Fact—there is no hard and fast rule that the cardio has to be the first exercise, or that it has to be done in the morning. Exercise was once meant to be done at dawn because it was believed that this was the best time for the body to exercise. However, today, when science has accepted the fact that different people have different peak times, you could choose the time that suits you best.

Fat Loss Exercise Myth No. 2—Your cardio is not successful unless it is done in the “fat burning zone”.

Fact—this myth might be one of the greatest of all time. There is no such thing as having to be in the “fat burning zone” in order to melt your fat. The weight loss depends on a lot of factors, and one would still lose weight most comfortably even if they do not enter the “fat burning zone” on the cardio.

Fat Loss Exercise Myth No. 3—You could burn fat simply by drinking some 8-12 glasses of ice-cold water.

Fact—I see that as an invitation to a terrible cold. Yes, drinking water helps weight loss indirectly since it fills up the stomach and allows less food intake. It is true that you need some 8- 2 glasses of water every day to stay in the pink because the body needs water to function well. However, it does not matter at what temperature you are drinking the water.

Fat Loss Exercise Myth No. 4—Negative calorie food is the best when you are on diet.

Fact—Logically speaking, if you could subtract（去掉）calories from the food you are eating you would come at a point when you reach at zero. Does that mean that when you consume negative calorie food, you are not eating at all? This is an expression just meant to symbolize the fact that the body takes longer to digest some food. That is all.

1. Which of the following is the author’s advice about exercising?

A．Exercise as early as possible.

B．Don’t exercise in the morning.

C．Don’t exercise as people once did.

D．Exercise at a time that is suitable for you.

2. What does the author think of “fat burning zone”?

A．It is of little value.	B．It is of great help.
C．It is uncomfortable.	D．It is actually harmful.

3. What does the underlined part “in the pink” mean in Fat Loss Exercise Myth No. 3?

A．In control.	B．In high spirit.
C．In good health.	D．In satisfaction.

4. Which is TRUE about negative calorie food?

A．It contains no calories.

B．Its calorie level is very low.

C．Its calorie level is very high.

D．It lowers your body temperature.