问题补充：
Frank , with his two sisters , London by train which at 8:30 next morning .
A. is leaving for ; will leave
B. are leaving for ; leaves
C. is leaving for ; leaves
D. will leave for ; will leave
答案：
A. is leaving for ; will leave
B. are leaving for ; leaves
(答案→)C. is leaving for ; leaves
D. will leave for ; will leave
解析：第一空考查主谓一致。With连接两个主语时，谓语动词取决于前者，leave用进行时态表将来，第二空，表达列车时刻表，几点出发，应用一般现在时态表将来，句意：弗兰克和他的两个妹妹要乘火车动身去伦敦，第二天早晨八点半的火车，所以选C。
