---John, why are you so upset?
---I my cell phone all morning but it is nowhere to be found.
A. am looking for
B. have looked for
C. have been looking for
D. had looked for
网友回答
A. am looking for
B. have looked for
(答案→)C. have been looking for
D. had looked for
解析：考查时态，由后面的时间状语all morning可以知道动作一直在发生，所以是C，句子意思“整个早上我一直都在找我的手机，但是任何地方都找不到”