What is the teacher trying to teach by telling the students to identify group verbs. How is a verb different from a group verb?

Thanks for your help.

2 answers

I've never heard of "group verbs" although I taught English grammar for many years.

She may have gotten her tongue twisted and means "verb groups."
You shouldn't question the teacher.
group verb: shouldn't question
modal: shouldn't verb: question
That is one way to get a group verb, a modal plus a verb.

Another is to use an auxiliary verb with a verb.
You haven't seen a better teacher in the 4th grade than this.
verb: seen auxiliary: haven't
group verb: haven't seen

http://www.usingenglish.com/glossary/verb-group.html