by mistake 错误地；由于差错:
I took your umbrella by mistake.
我错把你的雨伞拿走了.
I took your bag instead of mine by mistake.
我错拿了你的包,还以为是我的那.
according to 根据,按照；取决于；据…所说
They did everything according to the plan.
按照计划,他们做了一切事情.
According to the doctor,I need an operation.
按照医生的说法,我需要动一次手术.