题型:不定项选择 如图所示,人的质量为M,物块的质量为m,且M>m,若不计绳与滑轮的摩擦,则当人拉着绳向右跨出一步后,人和物仍保持静止,则下列说法中正确的是[ ]A.地面对人的摩擦力减小 B.人对地面的作用力不变 C.地面对人的摩擦力增大 D.人对地面的作用力减小 查看答案
题型:单项选择题 I was surprised to see()at the concert.A.those number of peopleB.that amount of peopleC.that number of peopleD.those amount of people 查看答案