猜想一：SO₂ $\stackrel{氧化}{\to }$ SO₃ $\stackrel{雨水}{\to }$ $H_{2}S{O}_4$

猜想二：SO₂ $\stackrel{雨水}{\to }$ $H_{2}S{O}_3$ $\stackrel{氧化}{\to }$ $H_{2}S{O}_4$

猜想三：以上两过程同时存在

有关上述猜想，收集一定量该地区刚下的雨水进行实验，下列判断中错误的是（    ）

下列不是食品保鲜方法的是（ ）

    Early this morning we all went to the Future Hall to have our graduation ceremony. The headmaster made a wonderful speech, and many of us ____ (move) to tears.

    Now the ceremony is over. We will leave school soon. I feel very excited because I am one of the best ____ (graduate). At the same time, I am a little sad because I have to say goodbye to my classmates and teachers. I want ____ (take) some photos with them and I will give some gifts to my teachers as well. In the past three years, I ____ (have) a great time in Red Star International School. I have learnt not only how to study, but also how to be a man. In ____ future, I will work much ____ (hard). I hope I can be an astronaut when I ____ (grow) up.

    Maria, Jane and Michael ____(go) back to their hometowns tomorrow and I will see them off at the airport. We will keep in touch ____ each other by sending emails, making telephone calls or writing letters. We will be good friends forever. I wish my classmates and teachers health, ____（happy） and good luck.