—What did Jack ask you just now?—He wanted to know how long when I reached the cinema.A.

问题补充：

—What did Jack ask you just now?

—He wanted to know how long when I reached the cinema.

A. had the film been on

B. the film had started

C. the film had lasted

D. had the film ended

答案：

A. had the film been on

B. the film had started

(答案→)C. the film had lasted

D. had the film ended

解析：考查宾语从句和现在完成时。know后是一个宾语从句，用陈述句语序，排除A、D；how long指的是一段时间，start是短暂性动词，不能和一段时间连用；last“持续”，是延续性动词，可与一段时间连用。故选C。