阅读理解
Dear Mr. Wang,
Someone comes to the office to see you in the morning, but you and your wife are out. He comes here at 10am. Because he is very busy, he goes away half an hour later. He tells me that he is your classmate at college(大学). Now he teaches Chinese in a high school(高中) in this city and he lives near the No. 6 Middle School. He is a very tall man with short hair. He wears a pair of glasses. He tells me his telephone number is 33426685. He is often at home at 7:00 pm. So you can call him in the evening.
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俗名¥作光气，是有毒气体。在一定条件下，可发生的化学反应为：
，下列有关说法正确的是