Don't be angry with us. We with you together, but we were busy with our final reports when you called in.
A. would eat out
B. must have eaten out
C. should eat out
D. could have eaten out
网友回答
A. would eat out
B. must have eaten out
C. should eat out
(答案→)D. could have eaten out
解析：D考察虚拟语气。句义：别生我们的气。我们本来可以和你出去吃饭的。但是当你叫我们的时候，我们正忙着做最好的报告。由we were busy with our final reports when you called in可知，事情发生在过去，首先排除AC。Must have eaten out一定出去吃了；could have eaten out一定出去吃了。Could have eaten out原本可以出去吃。故D正确。