现在完成进行时用来表示过去某一时间开始一直持续到现在的动作，动作可能还要继续进行下去。

　　【例如】

　　I have been working in BUAA since 1998.She has been waiting for her boss for almost an hour, but he still didn't come.The boy has been watching TV all morning.She ought to stop now; she had a headache because she____too long.(CET-4 2000, 1)

　　A) has been reading

　　B) had read

　　C) is reading

　　D) read

　　从句中看，读的动作过去已经开始，一直持续到现在，而且可能继续下去，所以她应该停止读，正确的时态应该为现在完成进行时，答案为A。