他真不知道。

He really doesn't know.

youdao

当他拉到大约四点钟的时候，他真不知道他是不是很快就要拉不下去了，就自言自语地说，“这是我剩下的最后一支曲子了！”

When he had scraped till about four o 'clock he felt that he verily would have to give over soon, and he said to himself, "There's only this last tune between me and eternal welfare!"

youdao

“你真棒！”他说道。“我真不知道你还有这两下子。”

"You were brilliant!" he said. "I didn't know you had it in you."

《柯林斯英汉双解大词典》

I became so obsessed with it that we drove up there so I could visit every school at which she had taught, and we actually found somebody who-- we knew he wouldn't like her because he was sweeping out the church, he worked for one of the churches, and she was very anti-clerical.

我实在太着迷于是就开车去了那,这样我就能去看她教过的每所学校,而且我们真发现一个人,我们知道他肯定不喜欢她,因为他当时正在打扫教堂,他在教堂工作,而她是反教会的

耶鲁公开课 - 1871年后的法国课程节选

Yeah, I don't know really what else to say. Just he's awesome.

我真不知道还能说些什么。总之就是他太棒了。

喜欢的电视节目 - SpeakingMax英语口语达人