Beginning in Brooklyn, N.Y. at nine p.m., Singer samples activities that might be taking place simultaneously around the world, moving west to east, including an anomalous Indian time- zone (half an hour different) and contrasting points in the same zones (Zaire and Switzerland). Lessac's cheerful, decorative paintings in a primitive style depict activities typical of both the hours and the locales. A useful, attractive concept book. (Picture book. 4-8)