下列运算正确的是（　　）

A．x²+x³=2x⁵

B．（-2x）²•x³=4x⁵

C．（x-y）²=x²-y²

D．x³y²÷x²y³=xy

29．How you feel about life and anything________depends on where you focus your attention．

A．in advance

B．in short

C．in turn

D．in particular