1 . The sudden ________ (appear) of a security guard caused them to drop the money and run away. (所给词的适当形式填空)

2 . His innovative ideas have made considerable ________ (contribute) to the field of renewable energy technology. (所给词的适当形式填空)

3 . The government needs to keep a _______ (平衡) between economic development and environmental protection to ensure sustainable growth. (根据汉语提示单词拼写)

4 . Elected as chairman of the c________ (委员会), he was full of confidence and energy. (根据中英文提示填空)

6 . She wanted to scream with ________ (frustrate). （所给词的适当形式填空）

7 . That’ll be $3 for the postage and $1.5 for the ______ (insure).（所给词的适当形式填空）

8 . Dinosaurs are often considered as giant creatures, but new research adds to ________(evident) that they started out small. （所给词的适当形式填空）

9 . I must ________ (表达感激之情) to those who have worked behind the scenes. （根据汉语提示完成句子）

10 . ________ (遗憾的是), I’ll have to meet my friend at the airport. （根据汉语提示完成句子）