羰基碳的正电性越强、空间位阻越小、亲核试剂的亲核性越强，醛酮的亲核加成反应越容易发生。（ ）
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半缩醛对碱、氧化剂、还原剂稳定，可分离出来。（ ）
A. 对
B. 错
无论酸还是碱催化下的酮的α－H的卤代反应，烯醇化一步都是决带步骤。（ ）
A. 对
B. 错
when is Mid-Autumn Festival ?
A. the 15th day of the 8th lumar month
B. August 15th in the calendar
C. full moon day
Paul and Sue decided to go to a restaurant. They reserved a table. But the restaurant was almost empty. So they ________________ a table.
A. mustn't reserve
B. needn't reserve
C. couldn't have reserved
D. needn't have reserved
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