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用质量相等的0℃的水和0℃的冰来冷却物体, ____的冷却效果较好.因为它在 ____过程中要 ____热量.
在等比数列{an}(n∈N*)中,若a1=1,a4=18,则该数列的前12项和为( )
寒冷的冬天,居民楼的玻璃窗上会“出汗”或结“冰花”.下列说法不正确的是( )
In many places in China, the old over 90 ____ (take good care of) not only by their family but also by the government.
如图是计算函数y=ln(-x),0,2x,x≤-2-2<x≤3x>3的值的程序框图,在①、②、③处分别应填入的是( )