新中国建立以来，中国先后印制了30多种版本的护照。其中1950版、1953版、1958版护照均为中俄文对照；1971版、1975版改为中法英文对照。这种变化的原因是（    ）

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.

如图，在平面直角坐标系xOy中，设椭圆 $\frac{x^2}{a^2}+\frac{y^2}{b^2}$ =1（a＞b＞0）的左、右焦点分别为F₁，F₂，右顶点为A，上顶点为B，离心率为e．椭圆上一点C满足：C在x轴上方，且CF₁⊥x轴．