题干

为使人们确知加碘盐中含碘物质的存在,研究性学习小组同学设计了一种简便的检验方法,利用该物质在酸性条件下与KI反应有单质碘生成的性质,选用下列生活中常见的物质就可完成。请你从下列物质中选出合适的一组
①自来水 ②食醋 ③淀粉 ④食糖 ⑤碘化钾试纸 ⑥碘酒

A:①③④⑤

B:②③④⑤  

C:①③⑤⑥

D:①②③⑤

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D

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    My transportation was unexpectedly smooth and I arrived at the meeting half an hour earlier. I kept my eyes on the restaurant door. Several customers entered, but not my friend. At 6:00 pm, she sent me a text message:“Urgent work to finish. Will be 20 minutes late.”

I had left my book in the office, so I spent the time thinking of my experiences of being late in China. On my first visit in 1985, punctuality was deeply rooted in the Chinese hearts. There were no traffic jams then.

    As a teacher in Canada, I always insisted on punctuality. I would open the classroom door to a late student for the first time and the second, but not the third. During the six years I worked for CCTV, I had a Chinese friend whom I often saw at lunch time, or after work. We used to meet at the subway station nearby. He was always late by 10-20 minutes. To myquestion, “You were busy?” he would surprisingly answer, “ No.” Once I asked him to check the clock in his office, he smiled.

    In March 2015, I got permanent residence (居住权) in China.The ceremony was scheduled for 9:00 am at the Public Security Bureau on the Second Ring Road. I told my driver I had to get there by 8: 40 am. “No problem,”he replied. But he thought he had time to drop someone off at the airport before picking me up. I desperately waited for him. Then, to rub salt into my wound, he had to stop at the exit of a gas station. Finally, I entered the room at 9:07 am ── the last guest to arrive!