Much of the concern over the past few years has centered on America’s yawning current account and fiscal deficits, and its effort to get China to let the yuan float more freely against the dollar. China, by contrast, sees its growth as tied to a stable currency, and may not want to introduce a more flexible exchange-rate regime, even after the 2.1% revaluation in July, pending alleviation of structural problems for which it is extremely difficult to set a timetable.