Question

4.        danger in the street at night,she had to go home with a friend.

(warn)

被警告夜晚街上很危险，她不得不和朋友一起回了家。

Answer 1

4. Having been warned of/Because she had been warned of/Warned of根据句意，前一部分应为原因，可用现在分词的完成式或原因状语从句来表示，亦可用过去分词短语来表达完成和被动之意。