Not The Best At Case Select Statement Writing...

Can someone simplify my feeble scratching at a Case Select statement, please?

I have two fields in a table (True/False): IsActive and IsDefault

I would like to convert some If...Else...Then statements to a Case Select statement which details what should be done when any of the possible states of the two fields exist.

Semi-Psuedo example in the (subform) Form_Current Event:
With Me
If !IsActive = True And !IsDefault = False Then
Do Something on the Parent form
ElseIf !IsActive = True And !IsDefault = False Then
Do Something Else on the Parent form
ElseIf !IsActive = True And !IsDefault = True Then
Do Something Else Again on the Parent form
Else
Do Something Entirely Different
End If
End With

What blows my mind is the Select Case Expression bit. I can't figure out how to write this. Any help is greatly appreciated.