改成被动句：One speaker read a statment which said that the rules are unfair.

改成a statment which said that the rules are unfair was read by pne speaker.会不会有头重脚轻的问题。 如果改成A statment was read by one speaker which said that the rules are unfair.行吗？

楼主的第二个改法有歧义，which别人会以为修饰speaker。
一般书面英语里，太长的修饰用逗号隔开
a statment, which said that the rules are unfair, was read by one speaker

你好！ l don’t know 参考资料：自己想 仅代表个人观点，不喜勿喷，谢谢。