In this task, you will be shown a correct English sentence. You need to generate an incorrect form of the input sentence.
One example: Students shouldn't work multiple full-time jobs.
Solution is here: Student's shouldn't work many full-time jobs.
Explanation: The possessive form is not correct in this instance and many should be multiple.

Now, solve this: Many studies over the last 5 0 years have shown that people who have fluoride in their drinking water have considerably fewer cavities than people who are not drinking water with fluoride . 
Solution:
Many studies over the last 5 0 years have shown that people who have fluoride in their drinking water are considerably have less cavities than people who have not drinking nonfluoridated water . 