Cao Yuan, a PhD student from China, had two papers published on strange behaviour in atom­thick layers of carbon that have opened up a new field of physics.
Pablo Jarillo­Herrero's group at MIT was already layering and rotating (旋转) sheets of carbon at different angles when Cao joined the lab in 2014.Cao's job was to find out what happened when one graphene (石墨烯) sheet was twisted only slightly with respect to the other, which one theory predicted would thoroughly change the material's behaviour.
Many physicists doubted the idea.But when Cao set out to create the subtly twisted stacks, he spotted something strange.Exposed to a small electric field and cooled to 1.7 degrees above absolute zero, the graphene—which ordinarily conducts electricity—became an insulator.That by itself was surprising.But the best was yet to come: with a slight change to the field, the twisted sheets became a superconductor, in which electricity flowed without resistance.
The ability to get atom­thick carbon into a complex electronic state through a simple rotation now has physics demanding to engineer exciting behavior in other twisted 2D materials.Some even hope that graphene could shed light on how more­complex materials superconduct at much higher temperatures.“There are so many things we can do，” says Cory Dean, a physicist at Columbia University.“The opportunities at hand now are almost irresistible.”
Hitting graphene's “magic angle”—a rotation between parallel sheets of around 1.1°—involved some trial and error, but Cao was soon able to do it reliably.His experimental skill was extremely important, says his supervisor Jarillo­Herrero.Cao pioneered a method of tearing a single sheet of graphene so that he could create a stack of two layers, from which he could then fine­tune alignment (微调校准)．
Cao loves to take things apart and rebuild them.A heart, he is “a tinkerer”， his supervisor says.On his own time, this means photographing the night sky using homemade cameras and telescopes—pieces of which usually lie across Cao's office.“Every time I go in, it's a huge mess, with computers taken apart and pieces of telescope all over his desk，” says Jarillo­Herrero.
语篇解读：本文是一篇记叙文，讲述了中国的博士生曹源通过实验发现石墨烯具有超导电性，能够让电流没有阻力地流过，科学界人士认为这个发现很有意义并高度评价了曹源的工作态度。
4．What is Cao Yuan's achievement?
A．Creating a method of piling carbon.
B．Finding the superconductivity of graphene.
C．Making equipment to twist graphene.
D．Starting research on a new field of physics.
解析：选B　细节理解题。根据第三段中的“But the best was yet to come: with a slight change to the field, the twisted sheets became a superconductor, in which electricity flowed without resistance.”可知，曹源发现只要磁场稍有变化，石墨烯薄片就变成了超导体，电流可以没有阻力地流过，故B项正确。
5．What do we know from Cory Dean's words?
A．The finding can be applied to all materials.
B．It is certain that many new discoveries are on the way.
C．The discovery suggests potential for other twisted 2D materials.
D．Physicists have been pushed to find more atom­thick carbon layers.
解析：选C　推理判断题。根据第四段中的“The ability to get atom­thick carbon into a complex electronic state through a simple rotation now has physics demanding to engineer exciting behavior in other twisted 2D materials.”可知，曹源的发现让科学家对其他扭曲的二维材料的超导电性的可能性很兴奋，故C项正确。
6．What does Jarillo­Herrero think is key to Cao Yuan's discovery?
A．His method of tearing sheets.
B．His knowledge of physics.
C．His curiosity about graphene.
D．His skill in experiments.
解析：选D　细节理解题。根据倒数第二段中的“His experimental skill was extremely important, says his supervisor Jarillo­Herrero.”可知，Jarillo­Herrero认为曹源的实验技能很重要，故D项正确。
7．What can we infer about Jarillo­Herrero?
A．He is an expert in telescope.
B．He thinks highly of Cao Yuan.
C．He appreciates messy offices.
D．He follows Cao Yuan's research.
解析：选B　推理判断题。根据最后一段中的“A heart，he is ‘a tinkerer’”及“Every time I go in，it's a huge mess，with computers taken apart and pieces of telescope all over his desk，”可知，Jarillo­Herrero夸曹源是一个修补匠，每次进入他的办公室，他的桌子上都堆满了零件，Jarillo­Herrero肯定了曹源的工作态度，故B项正确。