Evaluates CorrecText, Houghton-Mifflin's computer-based grammar checker that fully parses sentences and finds errors in grammar, style, and usage. Argues that, while CorrecText is an improvement over similar programs, it still cannot accommodate the syntactically ambiguous nature of English. Limits current design's usefulness to unedited prose. Appendix lists errors CorrecText is designed to catch. (DB)