在我们用外群比对前，我们应该知道一些系统发生的事情。
Before we can use outgroup comparison, we need to know something about the phylogeny.
邀上一群朋友到城市外的大自然去散散步吧。
Invite a few friends and get out of the city for a walk in nature.
像往常一般，正义宫外聚集了一大群喧闹的民众。
As usual, there was a noisy crowd outside the Palace of Justice.
一群孩子排着长队等候在唱片店外。
There was a long queue of children just outside the record store.
一群孩子排着长队等候在唱片店外。
There was a long queue of children just outside the record store.
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