求 a stack of 和 a pile of 区别

求 a stack of 和 a pile of 区别 a pile of和piles piles of和 a pile of有区别吗? a whole pile of a pile of ,后接什么 请问 a steaming pile of 什么意思 a pile of hay什么意思 There is a pile of books on the floor.There are a pile of bo there is a stack of books还是there are a stack of books a portion of a series of a pile of a panel of 的用法 a ton of / tons of / a pile of / an ocean of 等接可数还是不可数 it is a pile of toys on the