Sentence Correction

There's a lot of great free GMAT material on the web, but there's also a lot of crap. I've started this sticky thread to allow users to cite questions/material that they believe are not worthy of studying.

As you encounter practice questions/material that you think are bad, please respond to this thread and cite the source and/or question.

Also, please cite questions here (question number and source) where you think the OA is definitely incorrect.

Thanks!