警察和抗议者之间发生了激烈的冲突。

There was a violent ___clash between police and protesters.

这本书阐释了传统与现代价值观之间的文化冲突。

The book illustrates the cultural ___clash between traditional and modern values.

辩论演变成了关于政策问题的激烈争吵。

The debate turned into a bitter ___clash over policy issues.