did your uncle leave his hometown?---He for nearly twenty years.A. When; has leftB. W

问题补充：

--- did your uncle leave his hometown?

---He for nearly twenty years.

A. When; has left

B. When; has been away

C. How long; has left

D. How long; has been away

答案：

A. When; has left

(答案→)B. When; has been away

C. How long; has left

D. How long; has been away

解析：第一空，因为后面给的动词是短暂性动词，所以用特殊疑问词when ，因为how long 与延续性动词连用，而后一个空，后接for+一段时间，所以特殊疑问词需要是延续性的，故选B