separate the sheep from the goats 分辨好人与坏人；区分善恶；分清良莠

【例句】
The need for workers was so keen that the employer did not take the time to separate the sheep from the goats. It's no use pulling a long face, no one can help the fact that it is raining.
由于急需工人，雇主没有时间分辨好人与坏人。愁眉苦脸是没有用的，天要下雨时谁也没法子。

This test should separate the sheep from the goats.
这次测试会鉴别出好坏来的。