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【简答题】
SECTION C NEWS BROADCAST In this section, you will hear several news items. Listen to them care fully and then answer the questions that follow. Questions 21 and 22 are based on the following news. At the end o f the news item, you will be given 10 seconds to answer the questions. Now, listen to the news. ? The Russian Military says it will [A] kill 18 government soldiers. [B] leave the southern area of Vidinor. [C] derail the shaky peace process. [D] exact revenge for a Chechen rebel ambush.
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【简答题】写出下列单体的缩聚反应和所形成的聚酯结构。 (1) HO-R-COOH (2) HOOC-R-COOH + HO-R ’ -OH (3) HOOC-R-COOH + R ’ (OH)3 (4) HOOC-R-COOH + HO-R ’ -OH + R ’’ (OH)3