My experience with test training is that there is never enough material for multiple choice practice.
On the other hand, after a few weeks, the students get sick of doing the same type of practice.
With these slide shows, we've introduced a couple of practice innovations.
* The students get the correct answer right away. That way the teacher can do any explaining that may be necessary, or - if the student is working alone - to see what went wrong.
* In the case of the Spot the Mistake questions used in the second part of the TOEFL Structure and Written Expression Paper, having the right answer explained helps revision of the grammar behind the mistake. All three shows have the answers explained in very few words.