BEIJING, May 28 (Xinhua) -- China's telecommunications sector posted steady expansion in the first four months of the year, with emerging businesses such as cloud computing growing rapidly, official data showed. The sector posted 529.2 billion yuan (about 78.5 billion U.S. dollars) in aggregate revenue during the period, up 8.8 percent year on year, according to the Ministry of Industry and Information Technology. Emerging businesses, including big data, cloud computing, and internet data centers, expanded notably during the period. The emerging business revenue of China's three telecom giants -- China Telecom, China Mobile, and China Unicom, surged 35 percent year...