lead / led
The present and the metal versus the past.
Lead, pronounced leed, is the present tense: They lead the file. Led is the past tense and the past participle: They led the file. The file was led. Lead, pronounced led, is the metal. Do not write lead for the past of the verb.
Examples
UseShe led the meeting.
Usea lead pipe
AvoidShe lead the meeting.