问题
单项选择题
按分子极性大小进行分离的色谱材料是
A．硅胶
B．聚酰胺
C．离子交换
D．大孔树脂
E．葡聚糖凝胶
答案
参考答案：A
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按分子极性大小进行分离的色谱材料是
A．硅胶
B．聚酰胺
C．离子交换
D．大孔树脂
E．葡聚糖凝胶
参考答案：A
Learning experiences happen to us throughout our lives. Not long ago, I had one that I would like to 16 . I was going to Marblehead with my sailboat team. The team was racing down the highway at 85 mph 17 we realized we were 18 . Luckily, we saw a rest area ahead. I had a brand new $20 bill. I was so 19 because I had never had that kind of cash before. But spending it on 20 seemed like throwing it away. We all rushed into the pizza line. 21 I got a pizza and a drink, and walked to my table. About half way through the meal, I 22 I had not actually handed any money to the cashier. I had just 23 out, and nobody had noticed, I felt terrible. My conscience( 良心) opened its mouth and swallowed me in one big bite. I couldn’t 24 over it. I just couldn’t go back to the cashier and 25 for my stolen pizza. I was so upset that I 26 to give myself the pleasure of an ice-cream for 27 that someone would say, “ Hey, Jeff, why don’t you use the change 28 the pizza instead of that nice, new $20 bill?” I was not so 29 of my cash now. For the next two years, whenever I was 30 of the “pizza incident”, I would say to myself, “ Don’t think about it...” I have learned two things from this 31 . Maybe I was a fool for 32 in to my conscience, and being too stupid to appreciate a 33 pizza. But the real lesson is that even if you get away from what you have done, your conscience 34 up with you. This reflect the saying, “ A coward(懦夫) dies a thousand deaths; a hero dies one.” I was a coward and have felt terrible about that incident at least a thousand times. If I had been a “ 35 ” and gone back to pay for the pizza, I would have felt a little uncomfortable about it only once, or maybe twice.
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