质量检验是根据产品（）和有关（）运用一定的（）技术方法对产品进行质量特性的检查，判明其是否符合技术标准。
参考答案：技术标准；技术文件；检测手段
纯水在25℃和80℃时的氢离子浓度前者的量与后者的量的大小关系是 [ ]
A．大于
B．等于
C．小于
D．不能确定
The waterfall can be seen ____. Its sound may be heard ____ twomiles. It looks even more
beautiful ____, I think. [ ]
A. at a distance; in the distance of; from a distance
B. from a distance; in the distance of; at a distance
C. in the distance; from a distance; at a distance
D. in the distance; at a distance of; from a distance
