根据下列句子所给汉语注释，在句子空缺处写出单词的正确形式。

1. We had a long _________ (讨论) about the plan.

2. Driving on mountain roads always makes me _________ (紧张).

3. I _________ (写) her several letters, but she didn't reply.

4. He introduced his lovely daughter to the guests _________ (高兴地)

5. I couldn't decide _________ (是否) or not to go to the party.