1.   All too often we preferred to deny their existence than acknowledge the presence of mental illness.

2.   He acknowledged my presence with a quick wave.

3.   He wanted to acknowledge its presence and open himself to it.

4.   Max walked past her, without acknowledging her presence by the slightest alteration in his expression.

5.   The Prince smirked and Gaveston turned, for the first time acknowledging their presence with a condescending sneer.

6.   Tom acknowledged her presence by a brief glance.

7.   Tom caught my eye behind her back and winked to acknowledge my presence on alien territory.

8.   Usually a clerk at some point acknowledges my presence, comes up and asks me what I want.

9.   Was he even going to acknowledge her presence?

10.   He stopped at the door, waiting in vain for her to acknowledge his presence.