小丽的家和学校在一条笔直的马路旁，某天小丽沿着这条马路上学，先从家步行到公交站台甲，再乘车到公交站台乙下车，最后步行到学校（在整个过程中小丽步行的速度不变），图中折线ABCDE表示小丽和学校之间的距离y（米）与她离家时间x（分钟）之间的函数关系．

“每一次，都在徘徊孤单中坚强。每一次，就算很受伤也不闪泪光。我知道，我一直有双隐形的翅膀，带我飞，飞过绝望……”这首《隐形的翅膀》带给我们的启示有（   ）

根据方框里所给出的单词提示及短文意思填空。

The US public uses about 50 billion water bottles a year and most of those ____ bottles are not recycled, according to Elizabeth Royte’s book Bottlemanid: How Water Went on Sale and Why We Bought It.

More than $100 billion is spent every year on bottled water in the U.S. in many developing countries where there isn’t a safe ____ of tap water, bottled water is the only choice.

In the US, tap water is controlled by the government and often ____ for dangerous substances(物质). Each American drinks 79 litres of bottled water per year ____. The bottled water industry is so successful that it has outpaced milk, coffee, and juice in the number of gallons of drinks sold – putting it behind only beer and soda.