答案B。考查宾语从句中时态兼语态。“找零”动作发生在“离开”之前，故用完成时。
[备考启示] 现在完成时表示某个动作或过程在过去某个时间已经开始，现在已经完成或可能继续延续下去。
2.过去完成时
[例8] Father _____for London on business upon my arrival, so I didn’t see him
A. has left B. left
C. was leaving D. had left
答案D。父亲去伦敦出差这一动作在我去看他之前已经发生，故我没见着他。
[备考启示]某个动作或过程在过去的过去已经完成，与现在没有联系。
3.将来完成时
[例9] By the time Jane gets home, her aunt _____for London to attend a meeting.
A. will leave B. leaves
C. will have left D. left
答案C。等Jane回到家，她姑妈已离开去伦敦开会了。描述将来某一时刻前已完成的动作。
[备考启示]将来某一时刻前已完成的动作或过程用将来完成时。
五、一般现在时
[例10] The father as well as his three children ____skating on the frozen river every Sunday afternoon in winter. (辽宁2006NMET)
A. is going B. go
C. goes D. are going
答案C。描述现在习惯性动作使用一般现在时；此题还涉及主谓一致。
[备考启示]一般现在时表不受时限的客观存在、现在习惯性动作及现在状态或瞬间动作。