2:7, 2:1, 3:6.
2:4, 1:3, 3:5.
3:7, 2:1, 1:4.
2:1, 1:10, 1:4.
?:?, ?:?, ?:?.

I’m going to pay attention to a keyboard since it says "Keystroke" in the title.

I noticed that the first number in a pair was always 1,2 or 3. I think that means the 1st, 2nd or 3rd row, but I’m not sure if it means from top to bottom or not. Then I would guess that the second number is along the row, but I’m not sure if it means from left to right or not.

I’m going to make an assumption that they refer to letters (not punctuation) so the bottom row only has 7 letters, the middle has 9, and the top has 10. Well, from 1:10 in the fourth group, it seems that 1 means the top row. So 2 means the middle and 3 means the bottom.

Ok, I will start by guessing that the second number in a pair is from left to right. Let’s see what I get:

JAN
FEB
MAR
APR

There we go, it’s the 3 letter abbreviations for the months. So MAY comes next and that is

3:7, 2:1, 1:6