问题
选择题
__ his telephone number or e-mail address, she had some difficulty getting in touch with John.
A．Not knowing
B．Not to know
C．Not known
D．Not having known
答案
答案：A
本题考查非谓语动词。Not knowing…为现在分词的否定形式，在句中作原因状语，含伴随状况，相当于Because she didn't know his telephone number。