Abstract: Corpus-based and computer-aided teaching and learning tools for English-Chinese translation and bilingual writing mainly draw on a lexico-grammatical paradigm of data processing and data retrieval with taggings focused on parts-of-speech, syntax and semantics, with on-line facilities such as frequency counting, concordancing and collocation clustering. The inadequacy in data-processing in terms of explanatory coverage and depth is obvious when it comes to actual classroom teaching of translation, not to mention online self-learning. Moreover, systematic engagement between language reality and text/writing theories, for example, is necessary for annotation to be descriptive-explanatory in an informed manner, uplifting learners' learning experience from a mechanical perception of contrastive grammar to an awareness of textual functions and effects in bilingual and cross-cultural text transfer. To demonstrate how this could be made possible, this paper reports on an in-depth mode of data annotation in our current construction of an online platform for translation and bilingual teaching and learning. Examples will be shown with reference to various annotation principles following a system of tag-words as “signposts” to guide learners through their use of different materials, such as primary data, exercises, and annotations, to formulate guided learning pathways. Such a platform is designed to consolidate learners' grammatical knowledge, increase their textual awareness, as well as honing actual translation and bilingual writing skills.