Answer:
To manage one's temper, to calm them down.
I hope this helps.
Explanation:
”To keep one‘s temper“ is an example of an idiom. This means to stay calm and collected to not get angry. For example, the boy was about to lose his marbles but then his brother claimed him down. I used another idion in the sentence which is “lose his marbles.” That means that the boy was about to crazy/insane.
~Good luck
