I need to buy a new dress, so I am going to the shopping centre. There are many stores there, so I am likely to find a nice dress. It is for a celebration I will attend. I drive to the center. It is three miles away and traffic is good. When I arrive, I easily find a parking space near the entrance. I walk to the entrance. The shopping center is very large and modern looking. It was only built two years ago. It has three levels. I enter the centre and begin strolling through the main level. It is not very crowded today. There are escalators that you can take to reach other levels. There are many large windows, so it is almost like being outdoors. I can smell coffee and cinnamon buns from one vendor. A few birds are inside, and they fly around. There are pots with trees planted in them. From where I am standing, I can see exactly which stores I want to go into. I am confident that I can find the dress I want. 
Question: Why did they need to go shopping?
she needed a new dress for a celebration she'll be attending