by hand为什么不说by hands

by hand为什么不说by hands they made the cards____ A by hand B by hands Cwith hand D wi hand by hand 为什么只能用by the hand 不能用by the hand? Father By The Hand “at hand,in hand,on hand,by hand”分别是什么意思? 是with hand 还是by hand? by hand和with one's hand can be hand by hand翻译 请问下hand by hand的意思 ●hand by hand 手拉手,heart by heart by hand 与 by the hand的区别