At the end of Year 2 (Sec 2), you will get the chance to choose your subject combination choice for your Year 3 (Sec 3) of studies.
Not sure how to go about deciding? Here are some resources that might help:
Where Passion Meets Practicality: A Guide for Choosing Your Subject Combination - Read this to understand some ECG considerations you can take in choosing your subjects.
Decision Matrix - Download this template to help you weigh which subject combinations align more with your interests, aptitude and future aspirations.