they are believed to have already succeeded in their experiment.怎么翻译,是什么时态?

问题描述:

they are believed to have already succeeded in their experiment.
怎么翻译,是什么时态?

据说,他们的实验成功了。
实验成功---现在完成时

他们已经在这次试验中成功了, 是过去式 :)

他们的实验被认为已经成功了.
主句一般现在时的被动语态,不定式是现在完成时.