I only heard about it second-hand.

我只是听别人讲的。

《牛津词典》

I only heard about it secondhand.

我只间接听说了这件事。

《柯林斯英汉双解大词典》

"Somebody help my son!" I cried, over and over. But I only heard a woman scream.

“谁来救救我的儿子！”我一遍又一遍地哭喊着。但只听到了一个女人的喊叫。

youdao

I loved being away from home in places I had only heard about.

VOA: special.2010.01.30

And he ended with the position that the only way to put pressure on spending was by cutting taxes I never heard him use the phrase " but he subscribed to the starve-the-beast thesis.

到最后，他倒过来了,说，要想给政府施压，来削减财政支出,减税是必由之路,他倒是没有明确说,但依我看，他用的这招叫“把帽子扔过墙去。

斯坦福公开课 - 经济学课程节选

So I'm not -- I only heard about this indirectly.

WHITEHOUSE: Press Briefing by Press Secretary Jay Carney,

The India reception supposedly had around 400 people but I decided not to wait on line after I heard that only 7 people a minute could get through the security scanning machines.

FORBES: Exclusion and Inclusion at Davos

So far I've only heard about Virginia.

WHITEHOUSE: Press Briefing