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: However , if they just worked in the field which they already knew how to do well , they might feel sad and tired . 
Solution:
However , what if they just work for the field which they already know how to do well , they might feel sad and tired . 