In the context of Chinese learning English writing to learn and length approach is one of the highlighted concepts and practices. It entails sufficient comprehensible input and active interaction. It is found that the theme-based modules/units, if organized and performed meaningfully and closely related to the learners' life and experiences, will best integrate these three elements in the process of the second language learning, which is geared in some major aspects to the whole language philosophy. 'Writing to learn' is a product of reverse thinking. In a theme-based module/unit, a writing task of the same theme is put at its end with some requirements for language enhancement. It serves as an engine to learn other skills. In reality, it is not writing alone that functions in the SLA, but writing at the final stage that requires comprehended input and good qualitative interaction together to fuel SLA. An experiment of 20 weeks shows the positive results for the model.
