增加：在缺词处加一个漏字符号（∧）并在其下面写出该加的词。

删除：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1).每处错误及其修改均仅限一词；

2).只允许修改10处，多者（从第11处起）不计分。

    There was a time when my sister was very sad. She used to be a happy girl but was one of the top student in her class. But she lost her left leg in an accident when she is in high school. She was taken hospital and stayed for a long time. Feel very sad, she shut her in her room and refused to communicate with others. All of us were worried about her. One day she learned about a girl whom didn't lose heart though she lost her leg in an earthquake. My sister was deep moved. She had decided to forget the terrible experience and face her life bravely. Now she is living the happy life.

2016年12月，中共中央办公厅、国务院办公厅印发了《关于全面推行河长制的意见》。“河长制”，即由中国各级党政主要负责人担任“河长”，负责组织领导相应河湖的管理和保护工作。“河长制”工作的主要任务包括水资源管理保护、水域生态治理修复、水污染防治等六个方面。

结合材料，根据所学知识回答：

材料一:：伏尔加河流域流域内人口约占俄罗斯总人口的43%，机械、石化、电力和食品工业在国内处于领先地位，近300多年来曾发生多次洪灾，为此，流域内共修建807座各型水库以抵御洪灾。

材料二：伏尔加河流域简图及伏尔加河平均年径流量沿程变化表。

材料三：俄罗斯鲟鱼主要栖息在里海和亚速海—黑海水系内，属洄游性鱼类，每年2次洄游到伏尔加河淡水区产卵。春季洄游距离通常离河口仅100-300公里，秋季洄游距离离河口数千公里。