Need help on 1-4.

C. Given = {a, b): 1. Write a regular expression for the set: "All strings of a's and b's beginning with bb and not having three consecutive a's" 2. Describe in English the languages denoted by the following regular expression: (a + b)'b(a+ b) 3. Write a regular expression for the following language L(w) = {w/ w has exactly a single substring abaa or exactly a single substring babb) 4. Write a regular expression for the following language: L(w) (w w ends in bb and does net contain the substring aba)