For those of us lucky enough to always have enough food and water, it may be hard to imagine living through a drought. A drought

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问题     For those of us lucky enough to always have enough food and water, it may be hard to imagine living through a drought. A drought occurs for a (26)______of reasons, usually including a lack of(27)______and warm temperatures. Soil moisture seriously(28)______. Why and how do these climate events occur?
    As air spins around the earth, it rises and sinks over different areas of the(29)______. When air rises it cools and loses moisture. When air sinks, it grows warmer and(30)______moisture, drying out the land. Sinking air helps to form(31)______, such as the Sahara Desert in Africa. Warm,(32)______air can slow down cloud formation, which results in less rain and(33)______overall moisture.(34)______. The Dust Bowl that affected the plain regions of the United States was one well-known drought. An equally severe drought occurred in the United States in the summer of 1988. Rainfall over the mid-west, Northern Plains, and the Rockies was fifty to eighty-five percent below normal.
     (35)______. When a drought hits, there’s little that can be done to end it.(36)______.
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For those of us lucky enough to always have enough food and water, it may be hard to imagine living through a drought. A drought occurs for a(26)variety of reasons, usually including a lack of(27)rainfall and warm temperatures. Soil moisture seriously(28)reduces. Why and how do these climate events occur?
    As air spins around the earth, it rises and sinks over different areas of the(29)globe. When air rises it cools and loses moisture. When air sinks, it grows warmer and(30)absorbs moisture, drying out the land. Sinking air helps to form(31)deserts, such as the Sahara Desert in Africa. Warm,(32)sinking air can slow down cloud formation, which results in less rain and(33)lower overall moisture.(34)When these conditions occur in an area that normally receives enough rain to allow plants to grow and keep water sources refilled, a drought can follow. The Dust Bowl that affected the plain regions of the United States was one well-known drought. An equally severe drought occurred in the United States in the summer of 1988. Rainfall over the mid-west, Northern Plains, and the Rockies was fifty to eighty-five percent below normal.
    Sometimes over-farming and soil erosion contribute to drought, but there are also natural disasters that can occur even when soil is carefully preserved. When a drought hits, there’s little that can be done to end it.(36)Water and soil conservation can help, but until the rains come again there’s not much science can do.

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