问题 问答题

地下水质量分类划分为哪几类

答案

参考答案:《地下水质量标准》(GB/T 14848-1993)规定:依据我国地下水水质现状、人体健康基准值及地下水质量保持目标,并参照了生活饮用水、工业、农业用水水质要求,将地下水质量划分为5类。
Ⅰ类:主要反映地下水化学组分的天然低背景含量。适用于各种用途。
Ⅱ类:主要反映地下水化学组分的天然背景含量。适用于各种用途。
Ⅲ类:以人体健康基准值为依据,主要适用于集中式生活饮用水水源及工农业用水。
Ⅳ类:以农业和工业用水要求为依据,除适用于农业和部分工业用水外,适当处理后可作生活饮用水。
Ⅴ类:不宜饮用,其他用水可根据使用目的选用。

阅读理解

第三部分阅读理解(共15小题,每小题2分,满分30分)

A

Our first winter in Canada was the happiest we have ever experienced. We were living in the countryside then and had just arrived from Hong Kong that autumn. One evening in mid December snow began to fall. When we looked out of the window and saw that it was snowing, we all cheered. It was the first snow we had ever seen and we were excited. We could hardly wait  for the snow to stop so that we could go out lo play. Next morning when we woke up,it was still snowing. We switched on the radio and learned that more than ten inches of snow had fallen during the night and that since the roads were blocked, there would he no school that day. We jumped up and down for joy and beg mother to let us go outside to play in the snow, She said we could go out after breakfast if we dressed warmly and promised to come back as soon as we felt cold. When we went out, the snow had almost stopped. The roads, paths, gardens, and playgrounds were all hidden under a white blanket of soft snow. It was the most beautiful sight we had ever seen. Just then we saw some neighbours, children coming out to play. We ran over to join them. Together we built a snowman and a snow house. After that, we took turns sliding down a hill on a large piece of carboard. We were having so much fun when supper time came. Mother almost had to force us to go in and eat.

56. The children in the story had come from Hong Kong______ before the event described in the story happened

A. a year       B. the summer     C. a few weeks   D. the winter

57. The children were jumping with joy when they saw the snow because        .

A. they would go to school the following day

B. it was the first time they had seen snow

C. their mother would buy them warm clothes

D. they liked cold winter

58. When the children asked their mother lo let them go out to play, she ____.

A. asked them to go to school          B. refused to let them go outside

C. told them to switch on the radio .     D. told them to wait until after breakfast

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