Q$1$:

Assume S $=\{$a$,$ b$\}.$

Build a CFG for the language of all strings with a triple a in them. Build a regular grammar for the same language. Convert the CFG into CNF grammar.

Q$2$:

Assume S $=\{$a$,$ b$\}.$

Q$2-1)$ Build a CFG for the language defined by $($aaa$+$b$)*.$ Convert the CFG into CNF grammar.

Q$2-2)$ Give a leftmost derivation for baaabbaaaaaabb and aaabaaabbbaaa using the CFG grammar in Q$2-1.$