Read the following paragraph and underline the topic sentences.
A cowboy is someone who loves the cowboy's work. Since the hours are long - ten to fifteen hours a day - and the pay is $30, he has to. What's required of the cowboy is an odd mixture of physical vigor and materialism. His part of the beef - raising industry is to birth and nurture calves and take care of the calves' mothers. For the most part of his work is done on horseback, and in a lifetime he sees and comes to know more animals than people.