下列运算正确的是 $($　　 $)$

A． ${\left(x^3\right)}^2=x^5$B． ${(x-y)}^2=x^2+y^2$

C． $-x^2{y}^3·2x{y}^2=-2x^3{y}^5$D． $-(3x+y)=-3x+y$