同学们自发组织了一场环保宣传活动。

Tóngxuémen zìfā zǔzhī le yì chǎng huánbǎo xuānchuán huódòng.

The students spontaneously organized an environmental protection campaign.

这种自发形成的市场秩序值得研究。

Zhè zhǒng zìfā xíngchéng de shìchǎng zhìxù zhídé yánjiū.

This kind of spontaneously formed market order is worth studying.