He had taken every care to conceal his own presence.

He saw no way, now, to conceal his presence and destination.

They were making no effort to conceal their presence.

Figures that seemed to be trying to conceal their presence.

The other car made no effort to conceal its presence.

This time he makes no attempt to conceal his presence.

He did not bother to be careful of concealing his presence.

The garb of that figure helped to conceal its presence.

There was no longer any need to conceal her presence, she thought.

The smoke conceals his presence while he is able to see through it.