Chinese classrooms, whether on school grounds or online, have long suffered from a lack of interactivity. Many online classes simply provide recorded instructor lectures, which only reinforces the negative effects of passive nonparticipatory learning. At Shanghai Jiaotong University, researchers and developers actively seek technologic interventions that can greatly increase interactivity in large blended classes. They developed a cutting-edge mobile learning system that can deliver live broadcasts of real-time classroom teaching to students with mobile devices. Their system allows students to customise means of content-reception based on when and where they tune into the broadcast. The system also supports short text messaging and instant polls. Through these venues, students can ask questions and make suggestions in real time, and the instructor can address them immediately. This article describes this system in detail, and also reports results from a formal implementation of the system in a blended English classroom of 1000 students (with about 800 being online). As the data reveal, m-learning activities can much better engage students in the learning process. Students in this class changed from passive learners to truly engaged learners who are behaviourally, intellectually and emotionally involved in their learning tasks.