This worksheet tackles some of the most common prepositional mistakes that students make in general conversation. It includes a pre-quiz to test their knowledge, which is fun to do in pairs or small groups, as listening to them arguing over it, is funny. They were laughing too, not just me! Then there is an explanation on the reverse of the quiz with examples. This is by no means exhaustive, but the explanations highlight some of the key things to remember in order for students to use the correct preposition in certain instances. You may find they ask you more technical questions about the nuisances and you´ll have to delve deeper. There is also an extra bit of homework/classwork for them to practice. This normally takes my class around 1-1.5 hrs including explanation and practice. I devised this after so many of my students asked me for classes on prepositions. It works well from pre-intermediate up to advanced level if they still need some things ironing out.