Darling ,be a good boy /girl and brush off that sand.
You need to brush off that sand before you get into the house/car.
"Darling ,be a good boy /girl and brush off that sand."
By saying "Darling" you are encouraging them to complete the task without much trouble.Darling is a word we use to speak to our loved ones.
"You need to brush off that sand before you get into the house/car."
This is to issue an instruction that needs to be followed without argument or questioning.
Dust yourself off! Wipe off that sand...clean off all the sand, that is on you!
Clean yourself up! Lose the sand (coloquial)
Children are notoriously messy;-))
Sweeping/ Wiping /Dusting, Cleaning /Clearing off....and so on;
These are all valid expressions, mainly dependent on the source of the dirt;-)
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