问题
单项选择题 A1/A2型题
OPD经与HRP反应后，再用H2SO4终止反应后呈 （）
A.橙黄色
B.棕黄色
C.黄色
D.蓝色
E.红色
答案
参考答案：B
解析：OPD在HRP的作用下显橙黄色，加强酸如硫酸或盐酸终止反应后呈棕黄色，最大吸收峰在492nm波长。因此本题正确答案是B。
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OPD经与HRP反应后，再用H2SO4终止反应后呈 （）
A.橙黄色
B.棕黄色
C.黄色
D.蓝色
E.红色
参考答案：B
解析：OPD在HRP的作用下显橙黄色，加强酸如硫酸或盐酸终止反应后呈棕黄色，最大吸收峰在492nm波长。因此本题正确答案是B。
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| Behind our house is the start of a fascinating trail (小径). This trail is one of the old roads that wind through untold miles of forest. My 1 , Beans, and I walk the trail frequently. Normally, Beans sniffs alongside the trail to follow the smell of a deer track or 2 some cause known only to him. Beans is a white dog, quite handsome and very 3 . He not only understands what we tell him, but also often makes sounds as if he were trying to 4 back. One morning, we took a different route, which led us to an unfamiliar trail. I was sure this trail would eventually lead us to our familiar 5 . But, no. We seemed to be far off course. After two hours, I suddenly realized that Beans probably 6 the way home. So I urged, "Beans, take me home." He ran down a new trail. But it merely led to an intersection (岔道口) of trails. Soon it became 7 that we were getting nowhere. I began to picture the rest of the day in the 8 , without food or drink. We had walked about ten miles. But Beans seemed totally 9 . The sniffing and exploring was going well for him. Finally, we 10 a crossroad near a highway. Lady Luck suggested I should turn left. We did and 11 reached a cottage beside a field. I knocked on the door and explained my situation to an old man. He laughed and then drove us home. Since our adventure, I 12 that Beans probably knew all along how to get home. He was just having too much fan exploring new trails. | ||||
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