This paper describes TERRI, a CALL simulation lesson on English imperatives for students of English as a Foreign Language. The simulation was suggested by Winograd's (1976), which used a display with a table, a box, blocks, pyramids, and a ‘robot hand’. His program responded to questions about the objects and to commands to move them (using the ‘robot hand’). TERRI is a much-simplified adaptation of Winograd's simulation. The scene with several objects remains. The program sets a goal (in terms of object locations) for the student. The student gives commands in English, ordering TERRI to relocate individual objects. The program checks the student's grammar, vocabulary, and ‘sense’, requesting corrections and/or more information if needed. The lesson continues until the student achieves the goal or quits. As TERRI demonstrates, small-scale natural language processing permits the creation of CALL simulations of actual language use.