When Robert Mao describes the fantastic manufacturing opportunities his company sees in China, he speaks with mixed feelings. "For the first time in the modern era," he marvels, "we have an inexhaustible reservoir of good, trainable labor." But Mao, who as president and CEO of Nortel Networks China has worked in the region for 20 years, also worries about what that means for China's neighbors. For the foreseeable future, he says, almost all new investment by Nortel suppliers will go to China and not to other Asian countries.