be covered with 和be covered by 的区别，请造句哇

be covered with
被……盖满；充满着……
Any sharp corners, especially those facing you, should be covered with decorative photos or green, leafy plants.
任何尖角的地方，尤其是对着你的，应该用装饰的照片或绿色的大叶子植物盖上。
be covered by
被…覆盖
Each project will be covered by a plan of operation or project agreement to be signed both by the government and by FAO.
每个项目均有由政府和粮农组织双方签署的一项业务计划或项目协定。

be covered with 被…所覆盖,覆盖着,盖满…
The grass was covered with frost in the early morning.
The tree was covered with beautiful pink blossom.
be covered by ...:由...承担/负担/支付;被...掩护/报道/监视/控制等等,表示抽象的概念,后面接人,机构,或者组织.
These expenses are covered by the state.

be covered with一般较具体:
The mountain tops are covered with snow.
白雪覆盖着山顶.
be covered by一般较抽象:
This area has not been covered by the communication net.
这个地区还不在通讯网的覆盖之内.