请问此被动语态为何不加be动词的?

问题描述:

请问此被动语态为何不加be动词的?
It had “PASSED” written on it.
请问此被动语态中,动词write为何不加be动词,而直接写written的?

这个句子是省略句,完整的句子应该是
It has "Passed", which was/is written on it.
written 是 which引导的限定定语从句中的一个被动态. 省略which 和 be 动词,限定 PASSED 这个词,表示 PASSED 被写在 上面