Better sentence-writing in 30 minutes a day - Dianna Campbell 1995

End phrases
Using commas to set off phrases
Punctuating sentence combinations

Now read this sentence aloud:

Kurt Vonnegut has written some of the funniest and saddest books of the twentieth century repeatedly lamenting the exchange of kindness and love for progress and technology.

Go back and insert a comma after the word century; then read the sentence aloud once more. Again, it’s easier to handle with the comma, isn’t it? With the Kurt Vonnegut sentence, we have an example of an end phrase. In this kind of sentence, we have the independent clause first. For the convenience of your reader, the end phrase that follows the clause should be set off with a comma. Bracket and label the end phrase in the example sentence and mark the key parts of the independent clause.