"Supply the correct verb form" sounds like an order. Is this an instruction in an exercise or are you telling us what we must do?
"Verb form" is not a useful thread title. Titles should include some or all of the words you are querying. A good title would have been "He must be hurry" or something similar from your main sentence.
When are you going to submit this homework to your teacher?
Did you copy this question correctly?
Student or Learner