Question
no one would have attended the lecture if you told truth about the guest speaker
Answers
Writeacher
... if you had told ...
Sequence of verb tenses.
Sequence of verb tenses.
Writeacher
Here's a chart to help you understand the sequence of tenses better:
http://grammar.ccc.commnet.edu/grammar/sequence.htm
http://grammar.ccc.commnet.edu/grammar/sequence.htm