The verbs to do , to have , and to be are verbs that can be used

1.as a main verb.
2.as an auxiliary verb.
3.as either a main verb or an 4.auxiliary verb.

3 answers

http://grammar.ccc.commnet.edu/grammar/auxiliary.htm
from http://grammar.ccc.commnet.edu/grammar/verbs.htm

Let us know what you think.
they sort of help but there to long for me to read right now
To me, this is another badly written one. I believe 3 and 4 are correct.