I didn't know what else to say.

我不知道还能再说点什么。

《柯林斯英汉双解大词典》

I don't know what to say.

我不知道说什么好。

《牛津词典》

I had no need to open the letter—I knew what it would say.

我没必要拆开那封信—我知道里面会说些什么。

《牛津词典》

I might say I touched all the bases if I did what is necessary to complete a job or activity.

VOA: special.2009.04.12

I didn't want to make that judgment call for her when she said I am, what did she say?

我不想为她做判断,当她说，她说了什么？

哈佛公开课 - 计算机科学课程节选

because there's, I don't know what to say, over 50, 60 colleges, you know, that are recognizable in California

因为在加州有，我不知道怎么说，有五六十多所众所周知的大学，

加州的大学 - SpeakingMax英语口语达人

"I was pausing to formulate what I wanted to say, but it came across as if I didn't know what to say, " she says.

WSJ: The Decline of Eye Contact

Our conversations were short and stupid, and there was no way to say what I really wanted to say, so I talked about anything, the first thing that came into my head, some nonsense I hoped would make her smile.

NEWYORKER: Clara

If I was bugged, as I find very likely, I regret that those listening in did not pay more attention to what I had to say.

CNN: STORY HIGHLIGHTS