How can I negate an adjective in the past?

For example: 这是红色的。It is red. 这不是红色的。It's not red.

How could I say 'It was not red'? I read somewhere that 没有 only negates action verbs. If that's true, would the sentence in the past be the same (apart from time expressions) as the present?

  • past time might be indicated by 曾、曾经 or other adverb like 以前:曾经(以前)不是红色的,Does "it was not red" imply "now it is red"?
    – user6065
    Jul 22 '17 at 20:07

How do you specify past tense for 是?

From my answer:

You have to remember, unlike in English, we do not have past tense for verbs in Chinese grammar. Both "is" and "was" is written as "是" in Chinese.


You can say "它以前不是红色的". But it can imply somehow "它现在是红色的"。