A:of which
B:which of
C:of them
D:of that
不等式x2-ax-b<0的解集为{x|2<x<3},则不等式bx2-ax-1>0的解集为( )
在不计绳重和摩擦的情况下利用如右图所示的甲、乙两装置分别用力把相同的物体匀速提升相同的高度若用η甲,η乙表示甲、乙两装置的机械效率,W甲、W乙表示拉力所做的功( )
World Wildlife Fund ____(感激) very much the efforts that China has made to protect endangered species from being further endangered.