Instrumental records do not go back far enough to provide us with reliable measurements of global climatic variability on timescales longer than a century.
Their approach is flexible enough that in principle other important quality-of-life changes could be incorporated—for example, decreases in total emissions of pollutants and declines in crime rates.
Compared with the past, today's city has changed greatly, the streets are busy and row upon row of skyscrapers are everywhere. 24-hour cities with bright lights are sleepless.
One can say that a coach is helping your mental toughness for competition, and the imperious professor is at least preparing you for the vicissitudes of the real world.
In the Mesa Verde area of the ancient North American Southwest, living patterns changed in the thirteenth century, with large numbers of people moving into large communal dwellings called pueblos.
Writing in the last year of his life, he expressed the opinion that in two or three respects his mind had changed during the preceding twenty or thirty years.