2 sentences

1. 这个聚会是大家自发组织的。

   zhè gè jù​huì shì dà​jiā zì​fā zǔ​zhī de.

   This party was organized spontaneously by everyone.

   Source: Dong Chinese Dictionary

2. 这里的农民自发组建了一家供销合作社。

   zhè​lǐ de nóng​mín zì​fā zǔ​jiàn le yī jiā gōng​xiāo hé​zuò​shè.

   The local farmers spontaneously set up a supply and marketing cooperative.

   Source: Dong Chinese Dictionary