问题
选择题
—Hi，Mary.Would you like to go to the concert this evening?
—Sorry，Tom.________ tomorrow's lessons，I have no time to go out with you.
A．Not preparing
B．Not having prepared
C．Not to prepare
D．Being not prepared
答案
答案：B
根据句意可知，选项动词为原因状语，表主动，强调动作的完成性，相当于一个原因状语从句：As I haven't prepared tomorrow's lessons...故应选B(Not having prepared)。