摘要： The behavior of gases is explained by the kinetic theory. A. what do scientists call B. which it scientists call C. scientists call it D. what scientists call Section B Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need. A. recently B. affects C. pattern D. varied E. floats F. warm G. regularly H. mysterious I. effect J. evidence Big climate changes in the last million years might have come from something very small: dust from outer space. Earth changes between ice ages and warm periods in a(n) 41 that includes several cycles, including a 42 one that lasts 100,000 years. Scientists 43 suggested this cycle might be due to changes in the inflow of cosmic dust. The idea is that Earth 44 above and below the imaginary plane that runs through the sun and Jupiter, completing a cycle every 100,000 years. So maybe it encounters 45 varying amounts of dust during each cycle that produce the climate trend. Now there is some 46 , from ancient cosmic dust recovered in ocean-floor drilling near the Azores islands west of Portugal. The large quantity of the dust rises and falls with a wonderful 100,000 year cycle during the period analyzed, 253,000 years to 458,000 years ago. Periods of more dust are related to 47 climates. But that is a long way from showing that the dust 48 climate. Some scientists argue that it is not clear how cosmic dust would make the climate warmer while dust from volcanoes is known to make it cooler. They say the cosmic dust is so thin that it is hard to see how it could have any climate 49 . Nevertheless, the new study shows scientists have to take the cosmic dust idea seriously.

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