I can't be positive about what time it happened.

我说不准这事是什么时间发生的。

《牛津词典》

Can you be positive about what you saw?

你能肯定你看得真切吗？

《新英汉大辞典》

Be positive about your previous work experience.

积极面对关于你以前的工作经验。

youdao

"Well,I think the message from the United States personally coming here will obviously be a positive impact,in the sense that President Obama's administration is deeply concerned about the displaced people,".

VOA: standard.2009.06.03

One major difference between electron affinity and ionization energy is that when we talked about ionization energy, remember ionization energy always has to be positive.

电子亲和能,与电离能之间最大的不同就在于,当我们提到电离能的时候，记得电离能总是正的。

麻省理工公开课 - 化学原理课程节选

It turns out that it's going to be a little bit different when we're talking about positive ions here.

结果是当我们讨论阳离子时,有一些不同。

麻省理工公开课 - 化学原理课程节选

"There's not a whole lot to be positive about now, " said Cleveland Rueckert, an analyst at Birinyi Associates.

FORBES: Magazine Article

Quite how successful Kent have been in recent years is perhaps open to debate, what is not is that the county has plenty to be positive about.

BBC: Jones hopes Kent can bounce back

"We all tried to be very positive about it because the bride really loved them, " said Milane.

CNN: iReporters fear ugly bridesmaid dress, seek alternatives