生姜起源于东南亚的热带雨林地区，广泛分布于世界各热带、亚热带和温带地区。生姜储存在窖内（如下图所示）可长达3年。自从2008年价格飞涨以来就被冠以“姜你军”称号的生姜，在2011～2013年期间价格明显下跌。不过，沉寂了两年多之后，“姜你军”近年有卷土重来的势头。2015年广州市场上生姜零售价每斤已高达十五六元。据此完成下列问题。

根据上下文意思，用所给单词的恰当形式完成下列短文。

        Toby came back from England yesterday. Two months ago, Toby and his classmate____(enter) a robot competition for his school. More than one hundred  ____(school) around the country joined in it, and Toby's school____(win) the first prize. As captain of his team, Toby felt very proud. He said it was a wonderful experience. But the prize sounded more fantastic. It was a holiday in England. “When the plane took off, I still  ____(do) think it was real. It was like a dream." Toby said. Someone told Toby that the first prize of the robot competition next time____(be) a holiday in America. Toby hoped to enter it then.

已知点F₁，F₂是双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$（a>0,b>0）的左右焦点，点P是双曲线上的一点，且$\overrightarrow{P{F}_1}·\overrightarrow{P{F}_2}=0$，则△PF₁F₂面积为 (    )

SO₂通入I₂的水溶液中生成硫酸和氢碘酸（HI）：SO₂+I₂+2H₂O═H₂SO₄+2HI，可用此原理来测定空气中的SO₂含量．上述反应中，所含元素化合价降低的物质是（　　）