经过点P（0，1），Q（2，1）的直线在y轴上的截距为（　　）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

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：把多余的词用斜线( \ )划掉。

修改：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。

    I as well as my parents are going to New York City this month. I had been looking forward to visit there for a long time. It is one of the most beautiful cities all over the world. There are many places of interests where you can learn it in school. I'd also like to see the Empire State Building. Unfortunate, the Twin Towers were destroyed in September 11, 2001, and I would have the chance to see them by himself. Now I am getting ready for the excited trip. I am sure it will be an unforgettable experience.

工业上主要采用氨氧化法生产硝酸，如图是氨氧化率与氨﹣空气混合气中氧氨比的关系．其中直线表示反应的理论值；曲线表示生产实际情况．当氨氧化率达到100%，理论上r$\frac{n\left(O_2\right)}{n\left(N{H}_3\right)}$=____ ，实际生产要将r值维持在1.7～2.2之间，原因是____