_____ Li Bai, a great Chinese poet, was born is known to the public, but some won’t accept it.
A:That
B:Why
C:Where
D:How
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( )