His speech illuminated my mind and opened me to new possibilities.

illuminated 是动词 illuminate 的过去式，illuminate 由前缀 il-（表示"加强"）和词根 lumin（"光"）加上动词后缀 -ate 组成，字面意思是"用光照亮"，引申为"阐明、启迪"的意思。这里指演讲内容像光一样照亮了听众的思想。