Yesterday（our headmaster made a speech ______ environmental protection and we learned something about recycling of waste．（　　）A.onB. atC. to","title_text":"Yesterday our headmaster made a speech ______ environmental protection and we learned something about recycling of waste．（　　）A.onB. atC. to）

想必现在有很多小伙伴对于Yesterday our headmaster made a speech ______ environmental protection， and we learned something about recycling of waste．（　　）A.onB. atC. to","title_text":"Yesterday our headmaster made a speech ______ environmental protection， and we learned something about recycling of waste．（　　）A.onB. atC. to方面的知识都比较想要了解，那么今天小好小编就为大家收集了一些关于Yesterday our headmaster made a speech ______ environmental protection， and we learned something about recycling of waste．（　　）A.onB. atC. to","title_text":"Yesterday our headmaster made a speech ______ environmental protection， and we learned something about recycling of waste．（　　）A.onB. atC. to方面的知识分享给大家，希望大家会喜欢哦。

on"关于、在…之上、在…时候"；to"朝、到、对于"；at"在、以、向"，三者都是介词．．由题干"昨天我们的校长发表了关于环境保护的演讲，我们学到了一些回收废物的方法．"可知。

空格是"关于"，用on，因此答案应是on．故选：A．。

本文到此结束，希望对大家有所帮助。