There are clearly any number of questions that you could be asked about the first seven chapters of this great novel. Perhaps one key area that you could look at is the character of Kulfi, Sampath's mother, and how she is characterised and what she represents, as this should enable you to address one of the major themes of the novel, which is fate and destiny.
Kulfi is a character in the novel who is used to represent the idea that there is some kind of purpose or plan in life but that plan is very difficult to discern. Consider, for example, the way that her house is described as being "small for her big desire." Kulfi's desire clearly rules her as a character, and her lack of satisfaction with her present life leads her to constantly expect more and to reject the roles that society forces upon a woman of her position in society. Consider her insatiable hunger during her pregnancy and how she becomes obsessed with food, even going as far as sticking up many pictures of food on her walls "in desperation for another landscape."
As she nears the time of delivery, more and more this is something that can be seen in her character. She doesn't go to the bazaar and gossip and work with other women as was expected, merely choosing to stay in her hut. Her character is used to present the longing for meaning in a life that is made up of a series of mind-numbing and unfulfilling tasks. Reivising the character of Kulfi and her characterisation would be a very good way to prepare for your test. Good luck!