Dragging formula to skip column from 2 sheets

[swiftpunch]

Hey guys, bit of a problem right here.

I need to drag my formula and want it to skip the column like I tell it to.
So My formula is as follows: =(MEAN('ask yield green'!B:B))-(MEAN('ask yield conv'!B:B)) With 'ask yield green' and 'ask yield conv' being the names of my 2 sheets. then my second formula is =(MEAN('ask yield green'!D:D))-(MEAN('ask yield conv'!D:D)). Basically it takes the mean of 2 columns and subtracts them. I will manually type this formula several times referencing B,D,F,H,... etc but when I drag them it starts following a weird pattern. For example when I drag B&D the pattern will be: B,D,D,F,F,....
For clarity I only need to skip the column where i'm grabbing the data, I don't need to skip columns in the third sheet where i'm doing all the calculations.

Hope somebody can help.

[kvsrinivasamurthy]

If the first formula is in B3. C3 Shold be blank.
Select B3:C3. Hold the fill handle and drag across.