A、His great effort to prepare the talk. B、His perfect pronunciation of Mandarin. C、His success in speaking Chinese for half an h

Facebook founder Mark Zuckerberg recently surprised Chinese students when he spoke to them in Chinese. In a talk at Tsinghua University in Beijing, Zuckerberg spoke Chinese for about 30 minutes. Although his Mandarin was far from perfect, students and faculty cheered his effort.
    Zuckerberg’s talk raises a larger question: is Chinese the language of the future? Could it replace English as the world’s international language? Mandarin Chinese already has the most native speakers of any language. And, China may soon surpass the United States as the world’s largest economy.
    The study of the Chinese language is increasing in the United States and around the world. This year, about 60,000 American college students were studying Chinese. That is three times as many as in twenty years ago. A small but growing number of American parents are even sending their children to bilingual Chinese immersion schools. They think knowing Chinese could give their children a competitive advantage.
    Clayton Dube, the head of the U.S.-China Institute at the University of Southern California, thinks Chinese will grow in importance, especially for people who want to work and do business in China. But he does not think Chinese will overtake English any time soon.
    "As China rises, you can anticipate that more people will adopt the language. But is Chinese going to replace English? I don’t think so—certainly not in my lifetime, probably not in the next two, three, or four generations."
    English rose to prominence through the British Empire in the nineteenth century. American dominance in the twentieth century spread the language even further. Dube says American pop culture is one reason for English’s popularity as a foreign language.
    "American movies, music, television, video games have wide audiences... So far China’s success in this realm has been very limited. Chinese films, Chinese television shows, and Chinese music don’t have a huge following outside of China."
    Chinese is also a more difficult language to learn. The U.S. Foreign Service Institute estimates it would take a native English speaker 2,200 hours to reach professional fluency in Chinese. That is four times longer than it would take to reach the same level in Dutch, French, or Spanish. While Chinese grammar is much simpler, Chinese has a tone and writing system that is more difficult for adult learners to master.
    A recent survey by Gallup showed that only one in four Americans is multilingual, or able to speak more than one language. And most multilingual Americans are immigrants or the children of immigrants. For most Americans, Britons, and Australians, learning a foreign language is a choice, not a necessity. China Daily estimates that 400 million Chinese are studying English. That means China has more English learners than the U.S. has English speakers.
16. In Mark Zuckerberg’s talk at Tsinghua University, what surprised the students?
17. Why are some American parents sending their children to learn Chinese?
18. What increases English’s popularity according to Clayton Dube?
19. What do most Americans, Britons and Australians think of learning a foreign language?