why do the word (be)be in brackets when trying to put a verb in a sentence?

I have no idea. What sentence are you trying to put that verb into?

There_(be)some butter on the plate but there_(be)n eggs left in the fridge.Fill in blanks with appropriate form of verb.

OK.

Which form of the verb "to be" would fit in each place? Choose from the following:

am
is
are

What about when have is in brackets,what verbs can I use in a sentence?

The words am, is, are are all forms of the verb "be."

Which one fits here?
There ___ some butter on the plate...

And which one fits here?
... there ___ no eggs left in the fridge.

im confused about this sentence,Anny as well as her brother_(have)attended the university exam.

In that sentence, the subject is "Anny" -- but not "as well as her brother." If you say the sentence without "as well as her brother" would you choose "has" or "have" for that verb?

Anny ___ attended the university exam.

??