However, Picard couldn't be sure how they would react to his presence.

She didn't even react to his presence in her room.

And, perhaps, an intelligence that only now was beginning to react to his alien presence?

How will Hal react to our presence, after all these years?

He knew instantly that the eye had reacted to his presence.

But the metal body of the enemy around them, dead or dying, still had not reacted to their presence.

It took him another moment or two to react to her presence.

"You saw how my mother reacted to your presence here last night," she said.

Her gaze turned toward Data, but she did not react to his presence.

He wasn't certain how the Urrythans would react to his presence.