How to split string preserving whole words?

Question

I need to split long sentence into parts preserving whole words. Each part should have given maximum number of characters (including space, dots etc.). For example:

Answer 1

This works:

int partLength = 35;
string sentence = "Silver badges are awarded for longer term goals. Silver badges are uncommon.";
List lines =
    sentence
        .Split(' ')
        .Aggregate(new [] { "" }.ToList(), (a, x) =>
        {
            var last = a[a.Count - 1];
            if ((last + " " + x).Length > partLength)
            {
                a.Add(x);
            }
            else
            {
                a[a.Count - 1] = (last + " " + x).Trim();
            }
            return a;
        });

It gives me:

Silver badges are awarded for 
longer term goals. Silver badges 
are uncommon.