I need to know how to slove number 3 and 6

I have no idea what the s-grammar is. what is different between context

3. Find an s-grammar for L (aaa*b + ab*). 4. Find an s-grammar for L = {a"6" : n > 2}. 5. Find an s-grammar for L = {a62n : n > 2}. 6. Find an s-grammar for L = {amin+1:n > 1}