Regular Expressions to accept strings where every two successive 0s are followed by a 1 How do I define a Regular Expression for the language L = {w|every two successive 0s are followed by a 1} ?

I don't have any idea on how to even approach this problem, primarily because it says "every two 0s".
Take either 1, or 01, or 001 and repeat any number of times. Plus there can be a single 0 at the end.