What?!? "la rat"??? I thought it is supposed to be one or the other, not both together. So what is the rule here?
"Is" (to be) means "là", "very" means "rất". "Is very" = "là rất".
I thought "là rất" was bad grammar.
It is right grammar. That is a complete sentence. Maybe, you can use the sentence without "là" that is a sentence without predicate. In this case, we should write the complete sentence when the meaning of that sentence is emphasized more.
Why Việc phát huy? Can't i write directly "Phát huy truyền thống là rất cần thiết"? When does writing Việc become necessary?
"Việc" here may be a classifier for activities or actions, but it is not necessary here. I think it is not necessary in any case.