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. worked
D. have been working
答案：
A. work
B. are working
C. worked
(答案→)D. have been working
解析：考察时态。根据第一句我头疼，可知是过去发生的事情对现在的影响，。在根据too long可知应该使用完成进行时。句意：—我头疼。—难怪。你在电脑前面工作的时间太长了。
