Chinese is ___ a useful language _____ more and more foreigners want to learn it.
A:too, to
B:very, to
C:so, that
D:such, that
如图所示,水平转盘上放有质量为m的物块,当物块到转轴的距离为r时,连接物块和转轴的绳刚好被拉直(绳上张力为零).物块和转盘间最大静摩擦力是其正压力的μ倍.求:
填上适当的词。
一____歌 一____电 一____饭
一____山 一____星星 一____马
集合A={x|x2﹣2x≤0},B={x|y=lg(1﹣x)},则A∩B等于( )
原产于非洲的作物有( )