Our teacher was very happy because ______ failed the examination.
A：somebody
B：nobody
C：anybody
D：everybody.
“黑河是条内流河，从高大的祁连山北麓蓬勃北去，流经戈壁、盐泽，收纳万川之水，神奇的点化了荒芜的沙漠。”根据材料分析黑河流域的特征，你认为可信的是
下列物质属于纯净物的是（ ）
