Which word in the sentence is the auxiliary verb?

i did mail your letter for you.

a.
did

b.
letter

c.
mail

d.
you

which word in the sentence is the main verb?

did you eat popcorn with ann during the movie?

a.
during

b.
did

c.
eat

d.
popcorn

which word in the sentence is the main verb?

the peaches were placed in baskets of different sizes.

a.
placed

b.
peaches

c.
were

d.
different

which words in the sentence are the main and auxiliary verbs?

julia will not go to the concert.

a.
not go

b.
will not

c.
will not go

d.
will go