You are on the right track—it is actually the echo of all the leaves as a whole that matters.

你找对思路了——真正重要的是所有树叶整体的回声。

youdao

Her sweet voice chimed in beautifully with the echo of the music.

她的甜润的嗓音与乐曲的回声美妙地融为一体。

youdao

Last of all to disappear were the sounds of building; the echo of brick on brick and the continual whine of pulleys.

最后消失的是建造的声音；砖头碰砖头的回声和连续不断的滑车的嘎嘎声。

youdao

This echo effect can be heard on the recording of this huge hit for the Supremes in nineteen sixty-four, "Where Did Our Love Go?"

VOA: special.2009.05.11

At this point it's wonderful: Samson begins to echo Milton from the invocation that we've been looking at, the invocation to Book Three of Paradise Lost.

这里很奇妙：,参孙开始附和弥尔顿的祈求,我们刚才看到的失乐园第三卷中的祈求。

耶鲁公开课 - 弥尔顿课程节选

"We made some goofs that were kind of interesting,". "We didn't make the hallway wide enough to get a piano down, we forgot to put AC outlets in one of the studios, and we completely forgot the echo chambers, so we had to put them under the parking lot.

VOA: standard.2009.08.14

Redford said in the documentary that he didn't expect the echo of "All the President's Men" to remain for so long.

NPR: Discovery Documentary Revisits Watergate Movie

But if the honeymoon ends and Ekho Moskvy becomes the echo of public discontent, the station may find itself in trouble.

ECONOMIST: A spider's web of hidden controls

Many towns on the eastern plains of Colorado, far from the snowboarders and mountain-bikers, have heard just the echo of the latest boom.

ECONOMIST: The suburban West