【推荐2】More than 65 million years ago, at the end of the Cretaceous Period（白垩纪）, many species died off during a global disaster often called the K-Pg extinction. The end of the Cretaceous Period saw some very big changes in Earth’s oceans and on its lands. It wiped out up to 80% of all animal species, including the dinosaurs. But 20% of the animals that were alive with the dinosaurs did survive. What were these amazing animals? How and why did they survive while so many others disappeared forever? Behold the survivors of the K-Pg mass extinction.

Spider （Arachnid）

The earliest web-spinning arachnids （蛛形纲动物）produced silk from their abdomens about 386 million years ago. These ancient arachnids are closely related to today’s spiders. The original function of spider webs was probably to wrap eggs in a protective covering. Later, spiders evolved to use their silk to spin webs for catching prey. This ingenious invention helped them save energy while hunting and made it easier for them to survive.

Dragonflies （Meganeura 巨脉蜻蜓）

Today these flying insects have wings with a span of about 6 inches. But the earliest dragonflies used to grow to huge sizes 325 million years ago. The Meganeura dragonfly had a wingspan of almost 27 inches and would have dwarfed the largest modern dragonfly. In the oxygen-rich swamp environment of the Cretaceous, their large size helped Meganeura to absorb needed oxygen. But after the K-Pg extinction, the air and water contained less oxygen. Dragonflies adapted to their new environment by becoming smaller.

Crocodile （Sarcosuchus 帝王鳄）

The largest Sarcosuchus from the Cretaceous was 39 feet long. This is three times longer than the biggest modern crocodile. Crocodiles are predators and have probably hunted in much the same way for the past 225 million years. They have survived all this time by matching their relatively small size with their extremely powerful jaws that produce a great biting force.

Communication gap

Shi Jianfei, 21, is a mechanical manufacturing and automation major at Beijing Information Science and Technology University. He encountered an academic problem during the summer vacation but it took him a lot of determination to finally approach his professor at school to solve the problem. To his surprise, the meeting turned out to be quite pleasant.

But only a few students turn to their professors to ask for advice in solving problems or discuss academic topics with them. According to a poll of 2,636 college students conducted by MyCOS, a Beijing-based consultancy, more than a third of them contact their professors less than once a year.

Although most students and teachers are willing to communicate with each other, it seems that an effective communication mechanism is absent.

Shi says most of his professors share their contact details with students in the first class, but students tend not to take advantage of this.

“Communication usually takes place in class or between classes, because it’s difficult to get in touch with professors at any other time,” he says. “University professors always look very busy.”

Pressure

However, from the faculty’s perspective, students are too cautious about communicating with professors.

“They’re worried about asking questions they think may leave a bad impression,” says Du Xiguang, professor of chemistry at Northeast Normal University.

Wu created a QQ group in which students can discuss various issues with him, ranging from academic topics to personal problems.

“I find they are very talkative in this group because all of them are anonymous. But if they talk to me in person, they’re shy and nervous,” he says.

His view is echoed by Wu Qian, 22, an English major at Tsinghua University. Wu admits that when she encounters problems she prefers talking to her classmates and upper classmen.

“I think many students are too shy and passive, myself included. I feel more comfortable communicating with my peers,” she says.

Different styles of teaching

Cheng Haonan, 20, a space science and technology major at Nanjing University, offers another reason why students don’t form strong relationships with professors.

“We only meet our professor once or twice a week. That’s a lot less than the frequency with which we met our teachers in high school. Some professors can’t even remember my name,” says Cheng.

Du also attributes the shyness of many students to a change in teaching styles. In primary school, Chinese students get used to talking with their teachers because they’re like “nannies” who not only teach, but also watch out for their students’ personal development.

“In college, such communication isn’t *compulsory anymore and students aren’t pushed to discuss their ideas with professors,” says Du. “The real problem is that students aren’t yet ready to engage in adult conversation with professors. Some of them just expect professors to explain facts and help them prepare for exams, like in high school.”

Chen Yongmei, an associate professor at Beijing Forestry University, tackles this problem by taking the initiative. Since she only teaches one class a week, Chen invites one or two students for lunch every day. During lunch, they discuss academic and personal problems.

“Most students make use of this mechanism, but a few of them don’t,” she says. “In the latter case, I gradually lose the passion for communicating with them because this isn’t middle school. I’m happy to talk to them, but I don’t want to force them into a conversation they’re uncomfortable with.”