was和were加ing吗

was = "is" pass tense

were = "are" pass tense

"ing" is present tense

Yes, you can add "ing" in pass tense.
For example:

I was playing ball when it started to rain last Saturday.

was 和were的句子就是过去进行时,有was 和were的句子，后面跟着的动词也要是doing形式(不是can,是must)

不加，那些都是BE动词的过去式。

was were 不加ing
be 加ing

不加

no