I had no concrete evidence.

我当时没有明确而具体的证据。

《柯林斯英汉双解大词典》

There is no concrete evidence to support assertions that the recession is truly over.

没有任何确凿的证据支持经济衰退已真正结束的断言。

《柯林斯英汉双解大词典》

In seeking to describe the origins of theater, one must rely primarily on speculation, since there is little concrete evidence on which to draw.

在试图描述戏剧的起源时，人们必须主要依靠推测，因为几乎没有具体的证据可以引证。

youdao

There is literally concrete evidence of their work." Tony Hawk says skateboarding was once a sport on the edge of society.

VOA: special.2009.09.11

It was decided there was no prospect of tracking down suspects or getting sufficiently concrete evidence.

BBC: No prosecutions over Tower Hamlets vote fraud claims

Following up reported sightings, he's looking for concrete evidence that pine martens have made a comeback.

BBC: Springwatch returns to Ynys-hir reserve in mid Wales

The crux of the matter is there is no concrete evidence supporting the safety claim.

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