I know Google Translate is not always your best friend when it comes to Japanese, but when trying to compare what I'm understanding of my lessons and what I find in guide samples I'm a bit confused about the mandatory usage of the の particle.
1. 今年春休み 2. 今年の春休み 3. 今年春の休み 4. 今年の春の休み
They all look to mean the same thing: "Spring break this year".
Now for my comprehension of the の particle usage I thought number 4 would be more correct, while the guide uses number 2. And now I wonder: is the の particle optional? It there a general rule I can understand for when it has to be used and when not? Thanks in advance for replies.