* In the final decades of the 20th century, exciting developments began taking place in grammar teaching and research. First, there was renewed interest in an explicit focus on form in the classroom; publications argued that students benefit from grammar instruction (e.g., CelceMurcia, 1991a, 1991b; Celce-Murcia, D6rnyei, & Thurrell, 1997; Ellis, 1998; Master, 1994) and suggested new approaches to grammar pedagogy, such as teaching grammar in a discourse context (Celce-Murcia, 1991a, 1991b) and designing grammatical consciousness-raising or input analysis activities (e.g., Ellis, 1993, 1995; Fotos, 1993, 1994; Rutherford, 1987; Sharwood Smith, 1988; Yip, 1994). At the same time, computer technology was making it possible to conduct grammar studies of unprecedented scope and complexity. This research is part of corpus linguistics, the empirical study of language relying on computer-assisted techniques to analyze large, principled databases of naturally occurring language. Although only one aspect of corpus linguistics-concordancing-tended to be emphasized for classrooms (see, e.g., Cobb, 1997; Johns, 1986, 1994; Stevens, 1995), most ESL grammarians would agree that, by the end of the 20th century, corpus linguistics was also radically changing grammar research. Compare, for example, Longman's two reference grammars. The first, published in 1985 (Quirk, Greenbaum, Leech, & Svartvik), contained limited reports of corpus studies to supplement traditional intuitionbased description whereas the second, published in 1999 (Biber,