Question 1: Give context-free grammars that generate the following languages.
? { w ? {0, 1}? | w contains at least three 1s }
? { w ? {0, 1}? | w = wR and |w| is even }
? { w ? {0, 1}? | the length of w is odd and the middle symbol is 0 }
? { ai bj ck | i, j, k ? 0, and i = j or i = k }
? { ai bj ck | i, j, k ? 0 and i + j = k }