A:T1>T2,ΔH>0
B:T1>T2,ΔH<0
C:T1<T2,ΔH>0
D:T1<T2,ΔH<0
计算:
(1)(48﹣418)﹣(313﹣20.5)
(2)8+482-12-2-32.
平面α,β及直线l满足:α⊥β,l∥α,则一定有( )
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