____ the American economy expanded at an annual rate of 2.5 percent in July-September, it faced a long road to recovery. A. Since B. If C. While D. When
选C。 while
转折连词conj. 虽然; 而
翻译:虽然美国经济在7-9月份保持了平均2.5%的扩张,经济恢复仍然任重道远。