A、The industrialization of the United States. B、The development of individual timepieces. C、Reasons for increased productivity.

It is certain that everyone looks at his watch or at a clock everyday. Watches and clocks seem as much a part of our life as breathing or eating. And yet did you know that watches and clocks were scarce in the United States until the 1850s?
    In the late 1700s, people didn’t know the exact time unless they were near a clock. Those delightful clocks in the squares of European towns were built for the public. After all, most citizens simply couldn’t afford a persona] timepiece. Well into the 1800s in Europe and the United States, the main purpose of a watch, which by the way was worn off the wrist and on a gold chain, was to show others how wealthy you were. The word "wrist watch" didn’t even enter the English language until nearly 1900. By then the rapid pace of the industrialization in the United States meant that measuring time had become essential. How could the factory worker get to work on time unless he or she knew exactly what time it was? Since the efficiency was now measured by how fast the job was done, everyone was interested in time. And since industrialization made possible the manufacture of large quantities of goods, watches became fairly inexpensive. Furthermore electric lights kept factories going around the clock. Being "on time" had entered the language and life of every citizen.