________,Johnhasbeentoseveralforeigncountries.

Iknowitisn’timportantbutIcan’thelp________aboutit.

证明方程xxx1nn-1+n1的整数，在区间1,12内有且仅有一个实根；(II)记(I)中的实根为xn，证明limnnx存在，并求此极限

求曲线y=x^2与直线y=0，x=1所围成的平面图形绕x轴旋转一周所得旋转体的体积V.

Othersarguethatsincetheearthhasenduredalongstringoficeagesinthelasttwomilliontothreemillionyears,anywarmingis________tobetemporary.