Catch (someone) in the act
To discover (someone) in the process of doing usually something wrong: The boy was caught in the act of driving away the stolen car.
put on an act
To pretend by acting in a false way: She is trying to hide her real feelings by putting on an act of bravery.
take advantage of
(someone or something) To make use of someone or something for one’s personal benefit:
Let’s take advantage of this good weather and go for a swim.
Age- under age Not old enough; too young: This boy is under age for the tennis competition.
on the air
Broadcasting by radio or television: Silence please, we will be on the air in 20 seconds.