Nothing could be more wonderful.= Nothing could be nicer.= Nothing would please me more.没有比这更让人高兴的了。

I'm happy as a clam. 我很快乐。happy as a clam“非常快乐，非常幸福”

A: How's your life after marriage? 你婚后生活怎么样？
B: I'm happy as a clam. 我很快乐。

I'm so happy. = I'm really delighted. 我太高兴了。

I'm wild with joy.= I'm as happy as I can be.= I'm beside myself with joy. 我高兴极了。

I'm too excited to go to sleep.= I'm so excited that I can't go to sleep. 我兴奋得睡不着觉。

It's very exciting! 太令人激动了！

A: What do you think of the football game? 你认为这场足球比赛怎么样？
B: It's very exciting! 太令人激动了！

I'm really very enthusiastic about this. 我确实对此有强烈的兴趣。

A: Will you take part in our research program? 你愿意参加我们的研究项目吗？
B: I'm really very enthusiastic about this. 我确实对此有强烈的兴趣。

enthusiastic a. 热心的，热情的

I can't believe it. 我真不敢相信。

A: You won the championship. 你得了冠军。
B: I can't believe it. 我真不敢相信。

championship n. 冠军

Great! Terrific! Fantastic! 好极了！