"This is not a good time."

Translation: यह अच्छा समय नहीं है।

[peekpoke]

why " यह समय अच्छा नहीं है। " is a wrong translation?

[vinay92]

That would be 'This time is not good.'

Just like in English, attributive adjectives in Hindi come before the noun they modify. So, 'अच्छा समय'='good time'.

If an adjective comes after a noun, it is predicative which means that it is not a part of the noun phrase.

[peekpoke]

Thanks for your clarification.

[Meghan1991]

Can we leave out the है here since it's negative? Duolingo said that was wrong.

[vinay92]

No. Since there is no other verb in the sentence, the है can't be dropped.

[tizerzert]

Would it be correct if i say : यह एक अच्छा समय नहीं है

[vinay92]

It's not wrong but it doesn't sound very natural. Hindi uses the indefinite article (एक) very sparingly compared to English.

[BigAl82]

Can I use वक़्त for time here?

[vinay92]

Yes. You can report if it's not accepted.