• to be in the swim, to know the ropes, to know what's what
• have inside information
• to know sg through and through
• to know the inside of an affair
• no one knows his whereabouts
• to find one's bearings, to find one's way about, to get one's bearings, to know one's way about
• to take in the situation
• to get sy's number, to take sy's number
• to misread sy's feelings
• to be famous all over the world
• to be famous all the world over
• to take off one's hat to sy