investigate的名词形式：investigation

n.(正式的)调查，侦查;科学研究;学术研究

复数： investigations

例句：

So far, the police investigation has drawn a blank.

到目前为止警方的调查毫无结果。

The police have opened an investigation into the death.

警察已开始对这桩命案进行调查。

The matter is under investigation.

此事正在调查中。

The police have eliminated two suspects from their investigation.

警方通过调查已经排除了两名嫌疑犯。