$A.$$3x^{2}\times2x^{2}y=6x^{5}y,故此选项错误;$  $B.2a^{2}\times3a^{3}=6a^{5},故此选项正确;$  $C.(-2x)\times(-5x^{2}y)=10x^{3}y,故此选项错误;$  $D.(-2xy)\times(-3x^{2}y)=6x^{3}y^{2},故此选项错误.$  故选$B.$ 
下列计算正确的是．

(1) $$3{{x}^{3}}\cdot 2{{x}^{2}} y=6{{x}^{5}}$$ 
(2) $$2{{a}^{2}}\cdot 3{{a}^{3}}=6{{a}^{5}}$$ 
(3) $$\left( -2x \right)\cdot \left( -5{{x}^{2}} y \right)= -10 {{x}^{3}}y$$ 
(4) $$\left( -2xy \right)\cdot \left( -3{{x}^{2}}y \right)=6{{x}^{3}}y$$ 