Auxiliary Verbs

Time for a basic grammar view:

The verbs be, have and do are auxiliary verbs when they are used with a main verb to form questions, negatives, tenses and passives. Modal verbs, like  could and would, are also auxiliary verbs. Here are some quick examples:

"I am driving my car."

"We were looking for you."

"Do you know the way?"

What are auxiliary verbs

Auxiliary verbs in questions

• When ___ this bridge built?
  
  did
  is
  was
  were
  
  
• I believed, as __ my friends, that we would win.
  
  have
  does
  had
  did
  
  
• What ___ they want to eat?
  
  does
  do
  has
  are
  
  
• We ___ finished yet.
  
  hasn't
  don't
  didn't
  haven't
  
  
• Where ___ she live?
  
  are
  does
  do
  is
  
  
• ___ you seen my dog?
  
  Has
  Have
  Does
  Do
  
  
• Who have you ___ talking to all this time?
  
  had
  been
  were
  do
  
  
• She ___ done her homework.
  
  has
  have
  be
  did
  
  
• If Tom ___ asked me, I would have gone.
  
  have
  were
  has
  had