Auxiliary verbs - do, does, died This book covers the following topics: use of 'do' - structure - a - affirmative, structure - b - negative, structure - c - interrogative, structure - d - short answers use of 'does' - structure - a - affirmative, structure - b - negative. Structure - c - interrogative, structure - d - short answers use of 'did' - structure - a - affirmative, structure - b - negative, structure - c - interrogative, structure - d - short answers 'Do' and 'Does' are used in present tense while 'Did' is used in past tense.