cover with和cover by的区别

题目

cover with和cover by的区别
The pathway was completely covered by the dense foliage.这里cover表隐藏，掩住，by引导媒介。
The field is covered with snow.这里cover表盖住，被动语态。
不太清楚这个区别。

答案

cover with主要用在主动语态：i cover the table with cloth.
cover by 主要用在被动语态：the table is covered by cloth