"被覆盖" 的英文表达是 "to be covered". 来源方面，这个表达源于动词 "cover"，意为 "覆盖，遮盖，掩盖"。例句如下：

The table was covered with a white cloth. (桌子被一条白布盖住了。)

The city was covered in snow. (整个城市都被白雪覆盖了。)

She covered her face with her hands. (她用双手掩面。)

在此表达中，"to be covered" 的意思是 "被覆盖"。希望这些信息能够帮到您。