下列各句中,划线的词语运用正确的一项是( )
如图所示,一根橡皮筋固定在水平天花板的两点,在其中点悬挂一物体。当所挂物体的质量M=m时,橡皮筋与天花板夹角θ=θ1,橡皮筋张力T=T1;当M=2m时,θ=θ2,T= T2。则( )
——Do you think students should be allowed to do their homework with music on?
—— . If so, they can't concentrate on the study.
用科学记数法表示0.000031,结果是( )