"You can take as many
books as you like?" change into indirect speech

well stockyards mean a large yard containing pens and sheds, typically adjacent to a slaughterhouse, in which livestock is kept and sorted. and i'm assuming that by party you   mean a large group of people which does make sense because chicago is a very crowded place much like new york. stockyards tend to take up a lot of room due to needing the area for pens to keep animals in and the fact that stockyards are usually right by slaughterhouse where they process and distribute the product. so its much like a zoo but with some dead animal products close by.

answer: dinner and a movie with your friends this saturday night.

opportunity cost refers to the benefits that a person or business misses out on when choosing one alternative over another. opportunity costs are easy to miss, but they can be important for decision-making. in this example, the alternative that the person will miss out on is the opportunity to have dinner and watch a movie with friends on saturday, as he will have no money left after buying the cd.