Explanation: The sentence is in the past simple tense. 'Work' becomes 'worked'.
Explanation: The sentence is in the past simple tense. 'Start' becomes 'started'.
Explanation: The sentence is in the past simple tense. 'Stop' becomes 'stopped'.
Explanation: The sentence is in the past simple tense. 'Need' becomes 'needed'. For the negative, 'did not need' is used.
Explanation: The sentence is a question in the past simple tense. The auxiliary verb 'did' is used, so the main verb 'use' remains in its base form.