A:常温下为固态
B:在空气中含量也最多
C:可用来灭火
D:能使带火星的木条复燃
小雨用滑轮组提升重物.每个滑轮等重,不计绳重、摩擦和水的阻力.请画出与解题过程相应的受力分析示意图.
—It's too complex, I think.
—______. So we'd better make it easier for students to get involved.