Part of the paper was presented at the Thirty-Fifth Conference of the English Linguistic Society of Japan and in JELS 35 and Explorations in English Linguistics 31. I am deeply grateful to Professor Yoshiaki Kaneko and Professor Etsuro Shima, who have given me invaluable comments and suggestions since early versions of this paper. I would also like to express my gratitude to the members of the Department of English Linguistics at Tohoku University, with whom I had constructive discussions. I owe a very important debt to the audience at the Thirty-Fifth Conference of the English Linguistic Society of Japan and anonymous EL reviewers, who provided me with fruitful feedback. Last but not least, I appreciate the grammatical judgements off ered by Professor Max Phillips Jr. and Professor James Tink. All remaining errors are, of course, mine.