China may ban Facebook, but not its co-founder Mark Zuckerberg. The young billionaire delighted an audience of students at a prestigious Beijing university this week with a 30-minute chat in his recently learned Mandarin Chinese. He made no explicit mention of China’s ban on the social media giant, but an indirect reference to it drew laughter during the question-and-answer session Wednesday at Tsinghua University. Zuckerberg, whose company has long sought to enter China, noted Facebook already helps some Chinese companies in foreign markets, citing computer maker Lenovo’s ads on Facebook in India. “Speaking of China, I have a more difficult question for Mark, which I hope will not get me fired. What are Facebook’s plans in China?” asked the forum facilitator and Facebook employee Wei Xiaoliang, to the laughter and applause from the audience. “We are already in China,” Zuckerberg said in Chinese, to more laughter. “We help Chinese companies gain customers abroad,” he said.