语法与词汇
21.Every year a flood of farmers arrive in Shenzhen for the money-making jobs they______before leaving their hometowns.
【正确答案】
D
【答案解析】句意：为了离开家乡之前就被承诺的能挣钱的工作，每年大量的农民工涌入深圳。由句中arrive及before leaving their hometowns可知，该空应为现在完成时。job与promise之间是逻辑上的被动关系，故答案选D。