问题补充：
of danger in the street at night, she had to go home with a friend her.
A. Warning; following
B. Having warned; following
C. Warned; followed
D. Having been warned; following
答案：
A. Warning; following
B. Having warned; following
C. Warned; followed
(答案→)D. Having been warned; following
解析：句意，由于她被警告晚上在街上有危险，所以她不得不跟着一个朋友回家。根据题意分析可知这里需要现在分词作原因状语，而主语“她”和分词动作“警告”之间是被动关系，所以应使用被动形式，并且她被警告这个动作发生在她回家之前，故应用现在分词的完成式的被动形式。对于第二个空，“朋友”和“跟随”是主动关系，所以应用现在分词的一般式的主动形式。
