一个史上很难解释的英语句子------------务必高手帮忙

一个史上很难解释的英语句子------------务必高手帮忙They baby is just one day old and has not yet left hospital.She is quiet but alert（警觉）.Twenty centimeters from her face researchers have placed a white card with two black spots on it.She stares at it carefully.A researcher removes the card and replaces it by another,this time with the spots differently spaced.As the cards change from one to the other,her gaze（凝视）starts to lose its focus - until a third,with three black spots,is presented.Her gaze returns；she looks at it for twice as long as she did at the previous card.Can she tell that the number two is different from three,just 24 hours after coming into the world?Or do newborns simply prefer more to fewer?【The same experiment,but with three spots shown before two,shows the same return of interest when the number of spots changes.】Perhaps it is just the newness?请解释【】里的是不是插入成分?如果是的话,这好像是介词短语,重点翻译with three spots shown before two.然后标准整句翻译.