Choose the synonym of '$Obdurate^{\prime}.$

1.The old man spoke in a harsh voice. Which part of speech is the underlined word?

2.He spoke so softly that nobody could hear him. Which part of speech is the underlined word?

3.Although it rained, the match continued. Which part of speech is the underlined word?

4.He is good ___ mathematics.

5.She is interested ___ learning Japanese.

6.The proposal was rejected ___ grounds of insufficient data.

7.Which is the correct sentence?

8.Identify the correct sentence.

9.Despite the manager's calm tone, his email carried a subtle note of _____, warning the staff $\to meet the$ deadline.

10.The scientist's theory was dismissed as _____ until new evidence proved it correct.

11.Her speech was so full of unnecessary details that it became a long _____ on minor issues.

12.The new intern was surprisingly _____, quickly adapting $\to the fast-paced work$ environment.