It takes two to duet  , and one question for scientists is how these coordinated   performances arise -- in birds. Are they the result of cooperation, a way in which one pair signals to others that they've got it together? Or are they the result of conflict, evolving to avoid one partner's song interfering with the other's? A study of duetting in Peruvian warbling antbirds  suggests that it might be a little of both, and that context is everything. Joseph A. Tobias and Nathalie Seddon of the University of Oxford show in Current Biology that sexual conflict can cause the female of a pair that normally cooperates to "jam" the male's song by singing over it. The researchers exposed antbird pairs to recorded songs of other antbirds and monitored the songs the pairs produced. In one experiment, they played the songs of an intruding pair. In this case, the resident pair "both are likely to lose their territory, so both should cooperate," Dr. Tobias said. And they do. They produce a coordinated duet that in effect tells the intruders to keep away. But when the researchers played the song of a single female, the pair behaved differently. "You'd expect the resident female to be highly motivated to defend her position in the partnership," Dr. Tobias said. And that's what occurs. The male sings its heart out, flirting  with the single female, and the female of the pair does its best to interfere with the song by singing over it, apparently to make her mate less attractive to the other female. "It's clear that the male doesn't like what she's doing," Dr. Tobias said. The behavior "breaks up what is otherwise a very cooperative situation into a more complicated signal," he added. It's the first evidence of this kind of signal jamming among pairs, Dr. Tobias said. And in that it leads the male to alter its song to avoid the female's interfering notes, it shows that this kind of conflict could, over a long period, drive the evolution of coordinated song. What is the key factor of antbirds' duet? A) Their cooperation. B) Their conflict. C) The context. D) Their instinct.
C


(Question)
From cosy cabins and yurts to campervans and huts with character and mod-cons, winter camping can be cool, rather than just chilly, in these beautiful UK settings. Great Langdale, Cumbria Winner of the Great Outdoors accommodation of the year award 2014, this campsite at the head of a valley is a beautiful spot for winter walks. But while hiking should keep you warm by day, a selection of cosy hideaways will keep you _ at night. Visitors can choose from double-glazed wooden camping pods, which include heating and lighting or, for those who want a more boutique outdoors experience, luxury yurts furnished with Moroccan-style rugs and throws, fairy lights, lanterns and a wood-burning stove. And with the Sticklebarn pub - known for its real ales and good local grub - nearby, you should be able to slip into a pretty comfortable routine in no time. Standard pods from PS35 a night (two adults, one child), 01539 432733, nationaltrust.org.uk Vanellus, Elmley national nature reserve, Isle of Sheppey, Kent In the stunning surroundings of the Isle of Sheppey nature reserve, Vanellus is a large shepherd's hut. From the comfort of your abode (which is hooked up to electricity), you can gaze out through floor-to-ceiling windows as the sun rises and sets, watching birds of prey and other wildlife. The reserve can be explored on foot, or you can book a 4WD tour of the area. The farm has a lounge in a converted barn, where you can hang out or eat communally, but if you really can't bear to step into the cold, you can have meals - including hot bacon rolls for breakfast - delivered to your door. From PS180 for a two-night stay (sleeps two), 0117 204 7830, canopyandstars.co.uk The Cabin at NantyrOnnen, near Llandovery, Wales The Cabin is an unusual octagonal wood structure, built by local craftsmen keen to make an eco-friendly home. The electricity supply, for example, is powered by the nearby stream. From the sheltered veranda you can enjoy views across the hills, and the surrounding countryside is perfect for walking all year... A family of 6 (grandparents, parents and twins) wants to go for winter camping for 4 days. Which of the site is cheapest? A) Great Langdale B) Vanellus C) The Cabin D) Guilden Gate Glamping
(Answer)
A


Ques: On her first morning in America last summer, my daughter went out to explore her new neighborhood alone, without even telling my wife or me. Of course we were worried; we had just moved from Berlin, and she was just 8. But when she came home, we realized we had no reason to panic. Beaming with pride, she told us how she had discovered the little park around the corner, and had made friends with a few local dog owners. When this story comes up in conversations with American friends, we usually meet with polite disbelief. Most are horrified by the idea that their children might roam  around without adult supervision. A study by the University of California has found that American kids spend 90 per cent of their leisure time at home, often in front of the TV or playing video games. Such narrowing of children's world has happened across the developed world. But German parents are generally much more accepting of letting children take some risks. "We are depriving  them of opportunities to learn how to take control of their own lives," writes Peter Gray, a research professor at Boston College. He argues that this increases the chance that they will suffer from anxiety, depression, and various other mental disorders, which have gone up dramatically in recent decades. I am no psychologist like Professor Gray, but I know I won't be around forever to protect my girls from the challenges life holds in store for them. And by giving kids more control over their lives, they learn to have more confidence in their own capabilities. It's implied from Professor Gray's words that   _  . A) parents should always be around their children to protect them from risks B) more and more parents suffer from mental problems C) children are having more opportunities to take control of their lives D) giving children more freedom is beneficial to their mental development
Ans: D


The old saying that practice makes perfect seems to make no sense when it comes to schoolwork. Many educators today are looking for evidence to support the case for homework, but are coming up empty-handed. Mary Jane Cera is the academic administrator for the Kino School, and she maintains a no-homework policy across all grades. The purpose of the policy is to make sure learning remains a joy, not a thing that discourages social time and creative activity. At the Kino school, Cera says children often choose to take their favorite parts of school home. "A lot of what we see kids doing is practicing music with their friends, and taking experiments home to show their parents," she says. Surveys of Kino graduates suggest that the early control they are given over their education continues to serve them well into college. "One of the reasons that we continue to assign much homework is our obsession   with tests, although we can agree on the importance of kids doing better on tests through proper homework to some degree,"says author Alfie Kohn. In his book The Homework Myth, Kohn points out that no study has ever found a relation between homework and academic achievement and that if kids have no choice in the matter of homework, they're not really exercising judgment, and are instead losing their sense of self-control. However, many supporters of homework argue that life is filled with things we don't like to do, and that homework teaches self-discipline, time management and other non-academic life skills. Wherever the homework debate goes next, it's worth taking a moment to examine if we're doing the right thing about our children's education. The good news is -- it's never too late to start. Mary Jane Cera believes that   _  . A) learning should develop creativity B) homework should be done at home C) learning remains to be a difficult task D) homework serves as a ticket to success

A