But he added, he did not know for certain.

但是他补充说，他也不确定。

youdao

Mr Suttles said he "did not know for certain" why it had failed.

Suttles先生说他“并不十分确定”前种方案失败的原因。

youdao

I do not know, for certain, what they mean.

我不知道他们所说的确切含义。

youdao

I do not know, for certain, what they mean.

我不知道他们所说的确切含义。

youdao