听力原文: I once knew a man whose memory was very bad. Richard Rudd was so forgetful that he sometimes forgot what he was talking about in the middle of a sentence. His wife had to remind him constantly of his appointments, his classes--even his meals! Since Rudd was a professor at a well-known university, his forgetfulness often caused an embarrassment. It wasn't that he was unintelligent, as some critical people tend to gossip. He was just very, very absent-minded.
One hot summer day, Professor Rudd decided to take his children to the beach. The seaside town he planned to visit was about a three-hour train ride away. To make the trip more interesting for his young children, he kept the name of the town a secret. Unfortunately, by the time Rudd had arrived at the train station, the poor forgetful man had forgotten the name of his destination himself. Luckily, a friend of his happened to be in the station. He offered to take care of the children while Rudd went back home to find out where he was going. The professor's wife was surprised to see him again so soon, but she was amused when she heard what the matter was. She distrusted his memory, so she wrote the name of the town on a piece of paper. Satisfied that she had solved the problem, she sent her husband off again. Ten minutes later, she was astonished to see him outside the house again. What was the matter now?
"I can't find the piece of paper," said Professor Rudd.
(26)
A.Lack of confidence.
B.Lack of intelligence.
C.Carelessness.
D.Absent-mindedness.
第1题
用于提取挥发性苯醌的方法是
A.氧化铝柱色谱法
B.有机溶剂提取法
C.水蒸气蒸馏法
D.pH梯度萃取法
E.碱提酸沉法
第3题
根据羟基蒽醌酸性不同进行混合物分离的方法是
A.有机溶剂提取法
B.酸提碱沉法
C.水蒸气蒸馏法
D.pH梯度萃取法
E.氧化铝柱色谱法
第4题
根据羟基蒽醌酸性不同进行分离的方法是
A.氧化铝柱色谱法
B.有机溶剂提取法
C.水蒸气蒸馏法
D.pH梯度萃取法
E.碱提酸沉法
第5题
可用于提取具有游离酚羟基的蒽醌类化合物的方法是
A.酸水提取法
B.碱水提取法
C.水蒸气蒸馏法
D.pH梯度萃取法
E.氧化铝柱色谱法
第6题
根据羟基蒽醌酸性不同进行混合物分离的方法是
A.酸水提取法
B.碱水提取法
C.水蒸气蒸馏法
D.pH梯度萃取法
E.氧化铝柱色谱法
第10题
不是香豆素类化合物的提取方法有
A.水蒸汽蒸馏法
B.碱溶酸沉法
C.沸水提取法
D.有机溶剂提取法
E.酸溶碱沉法
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