Two keywords "input" and "get," in the BASIC programming language provide a metaphor of the processes of response and intervention in a dialogue situation. Computer teaching activities can be programmed using one or both of these commands. There are at least five main types: the quiz or overt teaching program, the text processsing program, the search, the game, and the simulation. In the last four, the computer is not a teacher but a provider and organizer of relevant language experience. Cloze passages, varieties of the Hangman game, and activities on predictable forms such as plurals, are activities based on the input command and consist of well-formed dialogue. Activities using the "get" keyword introduce the element of skill and timing. Another category of activities, simulations, can be relatively simple or complex. These involve an initial task and several possible solutions or routes to a solution. While there are drawbacks, the tasks one can carry out on computers are real enough to engross learners and they possess more versatility than printed visual aids. (AMH)