等距离抽样或机械抽样方法又称为（）
A.单纯抽样
B.系统抽样
C.分层抽样
D.整群抽样
E.多阶段抽样
参考答案：B
When I saw James, he ________ chess with his grandfather in the garden.[ ]
A) plays
B) played
C) was playing
D) had played
《苏州府志》载，明朝中期以后，苏州城里出现“无主者黎明立桥以待，听大户呼织，什百为群，延颈相望”的景象。这表明当时当地 [ ]
A．已形成了劳动力市场
B．失业现象比较普遍
C．小农经济已经解体
D．经济上以纺织业为主
