which of the choices are tips for impromptu speech preparation？

which of the choices are tips for impromptu speech preparation？
A.Don'；t speak generally
B.Don'；t tell cliché stories
C.Don'；t make language mistakes
D.Don'；t make logical mistakes
正确答案：Don'；t speak generally；Don'；t tell cliché stories；Don'；t make language mistakes；Don'；t make logical mistakes