He was driving a lorry load of bananas he came off the road at a bend and fell into the va

问题补充：

He was driving a lorry load of bananas he came off the road at a bend and fell into the valley.

A. since

B. until

C. when

D. while

答案：

A. since

B. until

(答案→)C. when

D. while

解析：考查连词。A. 自从……以来 B. 直到 C.当……时，动作有先后 D. 当……时，一边……一边……，强调两个动作同时发生。句意：当他脱离公路坠落山谷时，他正在开着一辆装了香蕉的卡车。故选C。