Hello. I'm preparing myself for the IELTS (for those who don't know it's an english test to certificate your language) and I have a doubt. In the speaking part of the test I shouldn't repeat the same words over an over again. One of the examples would be changing 'things' for 'stuff' but I don't really know if stuff it's an innapropiate word as it sounds quite informal to me. Am I right? Thanks so much