阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答题卡标号为16—25的相应位置上。 we must have water to live. __ 16________ the water we use is clean and fresh, it will make us ill. the animals __ 17________ (live) in and around lakes and rivers must also have clean water. our rivers and lakes supply most of our water. the clear, blue water found by the first a
