What does it mean to leave last dc unworked?

I have come to a line in my pattern that tells me to "dc in next 3 dc leaving last dc unworked, ch 2,". I don't understand what it means by leaving last dc unworked. Does it just want me to replace it with the ch 2? Why wouldn't they just state dc in next 2 dc, ch 2 in next dc? I'm really lost here...obviously. Any help would be greatly appreciated.

Thanks in advance,