So absorbed in the experiment that he didn’t even notice it was already over 12 o’clock.A

问题补充：

So absorbed in the experiment that he didn’t even notice it was already over 12 o’clock.

A. did he

B. he did

C. was he

D. he was

答案：

A. did he

B. he did

(答案→)C. was he

D. he was

解析：考查倒转句。把“so+形容词/副词”放在句首，后面的主句使用部分倒装的形式。本句是固定搭配be absorbed in…沉浸于…之中；句意：他如此沉浸于实验中，以至于他没有注意到已经是12点了。故C正确。