题目

The advantage human beings have to _________ the rare animals on the snowy mountain is worth discussing. A. do with                    B. play with                  C. have on                    D. take of 答案：D小芳用天平测一块实心塑料块的质量，天平平衡后如图甲所示，塑料块放入装有酒精的量筒，塑料块放入前后，量筒的情况分别如图乙、丙所示，塑料块的质量是    g、体积是    cm3，这种塑料的密度是    kg/m3．