$(1)$ For the given language A$=\{$ akbk $|$ k $>=0\},$ then it has CFG$,$ G $=($V$,\backslash$Sigma $,$ R$,$ S$),$ which V $=\{$S$\},\backslash$Sigma $=\{$a$,$ b$\},$ start variable S$,$ and rules S $->$ aSb $|$ b$.$