问题描述：
a group of 的用法.
a group of students is/are playing happily.
there is /are a gruop of students running on the grond.
单数还是复数.is 还是are
a group of students is/are playing happily.
there is /are a gruop of students running on the grond.
单数还是复数.is 还是are
问题解答：
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