28. --- Jack, don’t always copy what others do. ______ your head, please.

   --- Thanks for telling me.

A. Using     B. Used      C. Uses      D. Use

29. I’m sorry I know _____ about it. It’s a secret between them.

   A. nothing     B. something    C. anything     D. everything

30. You must be more careful and _____ the same mistakes you’ve ever made.

A. plan     B. follow     C. avoid     D. enjoy