b)HELPwithout help or without a person making it work 无外力的
The door seemed to open all by itself.
那扇门好像是自己打开的。
Examples from the Corpus
(all) by itself• The door's not going to close by itself.• Will the dog be safe left in the car by itself?• About twice as many, for depressionby itself.• But then, I think the Nagumo Force can handle this operation all by itself.• It's in there by itself.• Perhaps now he could see why the drawing was in a spaceby itself.• The growth in members is meaningless all by itself.• Let the fatuoussunshineby itself and let's head for the moon.• The threat of lawsuitsby itself is a majorfactor in driving up healthcare costs.• To begin with, by itself it doesn't produce anything.