If you want to place it in front of a sentence must have a comma between words and sentences, most popular//placed at the end of a sentence,//, although//has a structure like this:
To put it in front of the sentence. There must be a comma between the words and phrases most commonly placed at the end of a sentence // // though // is structured as follows.
If you want to put it in front of the sentence. Must have a comma separated vocabulary and sentence / / most popular placed at the end of the sentence / / though / / is structured as follows.