下列情况中,物体的质量发生了变化的是 [ ]
A.一根被拉长了的弹簧
B.一块被烧红了的铁块
C.从月球上采集一块岩石标本带回到地球上
D.正在刨床上加工的工件
答案:D
Every means ___ the river from being polluted.
A.are used to prevent
B.are used to preventing
C.is used to prevent
D.is used to preventing
三监