国际顶尖MBA申请交流平台--TOPWAY MBA

Clark and Florence Wallace, a husband-and wife medical team, worked steadily and efficiently through the night, but sipping their coffee the next morning, she noticed that he seemed disoriented.>>

B sipping their coffee the next morning, he seemed to be disoriented, she noticed>>

C as they sipped their coffee the next morning, she noticed that he seemed disoriented >>

D as they were sipping their coffee the next morning, he seemed, she noticed, disoriented>>

就是想问在这里用过去进行时为什么不可以呢，时态暗示不够明显么？

如果答案C的as前面没有句号或分号，而只是逗号，我觉得C就不能成为正确答案。理由是：as引导的是从句，如果你将as从句拿走或者放在句尾，就能清楚地看出C的问题，即将两个句子没有任何连词的用逗号连在一起，这在英文语法中，应该是不允许的。

As从句放在句尾，如下：

Clark and Florence Wallace, a husband-and wife medical team, worked steadily and efficiently through the night, she noticed that he seemed disoriented ，as they sipped their coffee the next morning。

所以，我觉得，只有A是正确选项，but是连词，后面是分词短语做定语，连词but将两个分句Clark and Florence Wallace, a husband-and wife medical team, worked steadily and efficiently through the night和she noticed that he seemed disoriented.

分开。

我的想法是因为d项 she noticed 是作为插入语，句子的实际主语只是he，这样就和前面的they 矛盾了。

我也选D, 逻辑意思高于一切,希望有NN 能指点D 跟C 相比为何错?