The boy was hit with a stick.
Their children were frightened by thunder.
Her room is cleaned with a vacuum-cleaner.
The test will be done by the best pupil.
These rings were sold by a newcomer.
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*Предлог with пишется, когда речь идет о том, каким инструментом/предметом кто-то другой совершил действие. А вот когда надо написать, кем совершено действие, мы используем предлог by.