Because of the lack of funds, the tunnel project has already fallen behind .A. situationB.

网友回答

A. situation
B. speed
C. insurance
(答案→)D. schedule
解析：句意：因为缺乏资金,隧道工程已经迟于预订计划。A. situation情况； B. speed 速度；                C. insurance保险； D. schedule计划。behind schedule是一个固定短语，意为比原计划慢。