of girls接单数还是复数 a group

单复数都可以，具体看句子，例如：

1、A group of girls then rally around him， shocked when they realise their friend is bleeding.随后，一群女孩子围了过来，当她们意识到自己的朋友正在流血的时候都震惊了。

2、A group of girls was waiting by the school.一群女孩子在学校旁边等着。

后接复数，a group of谓语动词的单复数根据of后面接的名词来判断，中文意思是一群女孩

A group of girls were playing with a ball in the street。一群女孩在街上玩球。