acknowledge:

vt. 承认；答谢；报偿；告知已收到

He saw me at the party but didn't acknowledge me.

他在聚会上看到了我却并没有向我致意。

identify:

vt. 确定；鉴定；识别，辨认出；使参与；把……看成一样

vi. 确定；认同；一致

The police dog can identify the approximate location of the criminal by his smell.

警犬可以根据气味辨别出罪犯的大概位置。