---I have got a headache----No wonder ．You in front of that computer too long ．A. work B.

问题补充：

---I have got a headache．

----No wonder ．You in front of that computer too long ．

A. work

B. are working

C. have been working

D. worked

答案：

A. work

B. are working

(答案→)C. have been working

D. worked

解析：考察时态。句意：我头疼。——不足为奇。你在电脑前工作的太久了。可知叙述的是已经完成的一直在进行的动作，故用完成进行时，选C。