设f(x)在[1，+∞)上连续，若曲线y=f(x)，直线x=1，x=t(t＞1)与x轴围成的平面区域绕x轴旋转一周所得的旋转体的体积为
[*]
且[*]，求函数y=f(x)的表达式．

He asked me ________ with me.

A．what is the trouble

B．what wrong was

C．what was the matter

D．what trouble it is