i need to find the verb of these sentence could you help me please if that is the sentence yestrday I noticed that a swarm of bees were or was buzzing round his head

Question

anonymous · Answer

i think the answer is were buzzing

anonymous · Answer

So the sentence is:  Yesterday I noticed that a swarm of bees were buzzing around his head

If that is the case, the verb (the action) is buzzing

anonymous · Answer

was, because the subject is a swarm and that is singular.

anonymous · Answer

If the sentence said Yesterday I noticed that  bees were or was buzzing around his head then the answer would be were because bees is plural