孩子们对老师的表扬反应很积极。

The children ___reacted positively to the teacher's praise.

她对突如其来的好消息惊喜地回应。

She ___reacted with surprise to the unexpected good news.

当酸和碱混合时，它们会快速发生化学反应。

When acid and base are mixed, they ___react quickly.

学生们强烈反对这项不公平的规定。

The students ___reacted strongly against the unfair rule.