质量为5kg的汽油,用去一半后,剩下的汽油( )
A:密度、比热容、热值都变为原来的一半
B:密度不变,比热容、热值变为原来的一半
C:密度、比热容变为原来的一半,热值不变
D:密度、比热容、热值都不变
若θ∈π4,π2,tan2θ=﹣37,则sinθ=( )
Joe has caused many problems and his dad can't ______ good ways to solve his trouble.