Questions 1-10

     Precipitation, commonly referred to as rainfall, is a measure of the quantity of water in the form of either rain, hail, or snow which reaches the ground. The average annual precipitation over the whole of the United States is thirty-six inches. It should be understood however, that a foot of snow is not equal to foot of precipitation. A general formula for computing the precipitation of snowfall is that ten inches of snow is equal to one inch of precipitation. In New York State, for example, twenty inches of snow in one year would be recorded as only two inches of precipitation. Forty inches of rain would be recorded as forty inches of precipitation. The total annual precipitation would be recorded as forty-two inches.

    The amount of precipitation is a combined result of several factors, including location, altitude, proximity to the sea, and the direction of prevailing winds. Most of the precipitation in the United States is brought originally by prevailing winds from the Pacific Ocean, the Gulf of Mexico, The Atlantic Ocean, and the Great Lakes. Because these prevailing winds generally come from the West, the Pacific Coast receives more annual precipitation than the Atlantic Coast. Along the Pacific Coast itself, however, altitude causes some diversity in rainfall. The mountain ranges of the United States, especially the Rocky Mountain Range and the Appalachian Mountain Range, influence the amount of precipitation in their areas. East of the Rocky Mountains, the annual precipitation decreases substantially from that west of the Rocky Mountains. The precipitation north of the Appalachian Mountains is about 40 percent less than that south of the Appalachian Mountains.                                 

1. What does this passage mainly discuss?

   A) Precipitation                    B) Snowfall

   C) New York State                D) A general formula