She had been in the office for days before anyone spoke to h

She had been in the office for days before anyone spoke to her.
这是书上的一句话,但是我感觉他错了,anyone 应该用在否定句和疑问句,而不是这句肯定句,对么?还有before这句的用法 它都是放在句子前面 就表示在什么之前 对么?