My new cipher with numbers

I have thought up one simple cipher. Hope it didn't exist before. Try to crack it!

Here is encoded one sentence in English consisting of three words.

$(2_ 2,5_ 2,7_ 5,8_ 5,9_ 4,14_ 4),(6_ 2,7_ 1),(3_ 2,5_ 4,30_ 4,70_ 2)$

• Number with index corresponds to one letter

Hint:

Numbers are not numbers

Answer

The answer is:

winter is here

Method:

- spell each integer (excluding index numbers) - two five seven eight etc.
- select letters from each word using index numbers - w i n t etc.