안녕하세요!
텝스문제를 풀다가
a series of~~ 뒤에 단수동사가 나오길래
예문을 검색했더니
단수도 나오고 복수도 나오는데..
뭐가 확실히 맞는건가요?!
읽어주셔서 감사합니당~!

A series of setbacks have put the whole project in jeopardy.
A series of economic indicators show that the Government are in trouble.
A series of refresher courses are required every three years.

A series of political scandals that has tainted the political stars of a generation.
A series of factors not so relevant to exporters comes into play for importers.