题目

Gary Locke, 61, who comes from a Chinese background and even looks Chinese, became the new US ambassador（大使）to China. “I can think of nobody who is more qualified than Gary Locke.” President Obama said. Locke’s new position is clearly a sign that US President is trying to improve relations with China. When he made his first speech to the Chinese press in Beijing, Locke said,“I think ,being a Chinese-American, I have a greater understanding of the history and culture of China, but I am here as a representative of the US government.” Before becoming ambassador to China, L设a是实数，且，则实数a=（ ）A．-1B．1C．2D．-2