Those skilled in the art willbe aware of the time requirements for a particular reaction.In one particular embodiment of the present invention, the combination comprises a first reagent, M1'-L1'-Z', wherein M1 ' is a first moiety, L1' is a bond or a linking group and Z' is an amine group and a second reagent,X'--CH.dbd.CH--(C.dbd.O)(L4'M2), wherein M2' is a second moiety and L4' is a bond or a lin