题目

在铜、塑料、橡胶、人体、干木材、大地等几种物质中，下列四组选择中都是导体的一组是:A.铜、塑料、人体; B.人体、干木材、大地;C.塑料、橡胶、干木材; D.铜、人体、大地. 答案：DToday, the forests have almost gone. People must ________ down too many trees.A. stop to cutB. stop from cuttingC. be stopped to cutD. be stopped from cutting