Rainbow alphabet doggerel (C,D)

C is for CucumberThe crazy cook would prepareHis favourite dish with great care-Curried crab with cold custard,Crumble cake with Colman's Mustard,Chocolate and cheese with codAnd sliced cucumber (which seems odd)All clumped together with clammy rice,The taste of which he claims is nice.___D is for DoThe little riddle of exampleIf I doWhat you doAnd he doesThe sameThen they doWhat we doWho first