and bumblebees obviously declining in some parts of Europe. Previously, attention on the decline of bee populations has focused on causes including habitat loss, pesticide use and the spread of bee parasites (寄生虫). But the work by Kerr's team found something different.

　　"For every species, there is one or two species declining and others that are not moving at all," says Kerr. This shift has also been observed in other species, such as butterflies. But due to a new cause--- the rise of temperatures instead of total pesticide use, a change in land use or parasites, bumblebees -unlike butterflies ---have failed to extend the northern boundaries of their ranges into the territory that is now habitable for them, so bumblebee species across Europe and North America are declining rapidly, the latest study led by Kerr's team finds. "Our data suggest that the new factor plays a leading, or perhaps the leading, role in this trend," says Kerr.

　　"This study show that a fourth factor is also beginning to affect it. It is likely that the combined stresses from all of these pressure will have destructive impacts on bumblebees in the not-too-distant future," says Dave Goulson, a bee researcher at the University of Susssex, Brighton, UK.

　　Exactly what can be done to help bumblebees is not clear. Kerr's team suggests that relocating colonies might be an answer but Goulson says that because the insects are mobile they are capable of moving northwards if there is suitable habitat available.

1. What does the move of the bees' southern limits lead to?

A. The birth of new bee species B. The rise of the bee's population.

C. The evolution of the bees D. The reduction of the bee's habitat

10. What's the new cause of bee populations' declining according to Kerr?

A. Habitat loss B. Pesticide use C. Climate change D. The spread of bee parasites

11. Which statement may Goulson agree with?

A. Relocating bumblebees isn't much good

B. The findings of Kerr's study are doubtful.

C. The future of bumblebees is still promising.

D. Knowing bumblebees' living habits is the most urgent

12. What kind of writing is this passage?

A. A book review B. An announcement

　　C. A scientific report D. An official report.

"A photograph that one has taken of oneself, typically with a smart phone or webcam and uploaded to a social media website" is the definition of "selfie" in the Oxford English Dictionary. In fact, it wasn't even in the dictionary until August of last year. It earned its place there because people are now so obsessed with (对...痴迷) selfies---we take them when we try on a new hat, play with our pets or when we meet a friend whom we haven't seen in a while.

But is there any scientific explanation for this obsession? Well, you should probably ask James Kilner, a neuroscientist (神经系统科学家) at University College London.

Through our lifetime we become experts at recognizing and interpreting other people's faces and facial expressions. In contrast, according to Kilner, we have a very poor understanding of our own faces since we have little experience of looking at them--- we just feel them most of the time. This has been proved in previous studies, according to the BBC.