问题补充:
how to solve the problem, the little boy turned to his father for help.
A. Not knowing
B. Having not known
C. Not having been known
D. Not known
答案:
(答案→)A. Not knowing
B. Having not known
C. Not having been known
D. Not known
解析:考查现在分词的否定做状语,句意是:不知道怎么解决问题,小男孩向父亲求助。The boy和know是主动关系,not发在现在分词前面。选A。