Please check my answer

There was one student still taking the exam when the bell rang.

Student is the subject and exam is the simple subject.

9 answers

You're half right.

Student is the simple subject. What was the student doing?
taking the exam
Yes. Which one of those is the verb?

Also note the helping verb.

https://www.englishclub.com/grammar/verbs-classification-helping.htm
there is the verb.
helping verb is was
am I close?
I don't see any action in helping. Plus I already told you that one of three words is the verb!

Yes, "was" is the helping verb.
Taking is the verb
Yes. The verb is WAS TAKING.
Ok I think I got it. The complete subject is taking the exam
Huh??????