in sb's presence
当着某人的面,有某人在场in the place where sb is; with sb there
I was often silent in her presence.有她在场,我常常无话可说。
presence of mind
镇定自若ability to remain calm and act quickly and sensibly in a crisis
Thanks to his presence of mind, the children were saved.由于他的镇静,孩子们得救了。