Mother may have hidden Luke's plate in the cupboard out of frustration or a desire to teach him to take responsibility for his own things. She may also want to encourage him to help out more around the house with small tasks like putting away his own dishes.
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A by-motive is a hidden motive.
An ulterior motive is a motive that they have beyond the main motive. They often do not show that they have this motive and it is often not good. The ulterior motive is almost always has it for their own good only.
The police are trying to find the motive of the murder.Money is my main motive.
motive
(Early 20th century slang) To coerce someone to accept a line of reasoning or carry out an act they normally wouldn't by 'cleaning up' or hiding the requestor's ulterior motive; Fraud.
1 - Transaction motive 2 - Precautionary motive 3 - Speculative motive
A motive is a smaller part of the larger theme! :)
my motive in school is to get good grades
a motive is something a criminal has
my motive in school is to get good grades
the motive of the Normandy invasion was to liberate the french from the nazi Germans who had invaded years before