ADG,BEH,CFI,___,___,___

ADG,BEH,CFI,___,___,___

Looking at this pattern, we see:

1. the first term starts with A and increments by 1 letter
2. the second term starts with D and increments by 1 letter
3. the third term starts with G and increments by 1 letter

So terms 4, 5, and 6 are:

• DGJ
• EHK
• FIL