Kakhol hu tseva meshakhnea
What about "כחול זה צנע משכנע"?
Whoops, typo. Thanks.
המשפט הזה נוראי
What is a convincing colour? The phrase means nothing to me.
I thought the copula was optional, but I was marked wrong for omitting הוא. What is the rule on that?
Well you have two nouns next to each other. In those cases you need copula.