Complete the following sentences as required（根据所给要求，完成下列句子）：

【1】My friend knew something about the car accident. （改为否定句）

My friend ________ know ________ about the car accident.

【2】My mother is as old as my former teacher. （保持句意不变）

My mother and my former teacher are of the ________ ________.

【3】The new dictionary as a gift for my friend cost me 100 yuan. （改为反意疑问句）

The new dictionary as a gift for my friend cost me 100 yuan, ________ ________?

【4】the police, she, her missing dog, to, described（连词成句）

________________________________________________________________________.