Correct option is C
they are structural errors needing more practice in correct forms
The errors described, where students are unable to use the correct form of verbs for various expressions, are typically structural errors. These errors arise from a lack of understanding or confusion about the language rules and structures. The appropriate action is to provide more practice in the correct forms, focusing on the varied and contextual use of verb forms. Over time, with consistent practice and correction, students can overcome these errors and use verb forms accurately and confidently.