a series of 和a pair of 后面谓语动词用单数还是复数?

a series of 和a pair of 后面谓语动词用单数还是复数? a series of a series of和a trail of的区别 Peasants are living a good life because of good harvestsA.a set of B.a pair of C.a series of D.a piece of 是a series of factors还是a series of reasons a pair of shoes a pair of couple a pair of a pair of Need a pair of a series of a serious of 区别 a pair of和a piece of的区别 a pair of和 a piece of有什么区别 a couple of 和 a pair of 的具体区别, 如何区分a pair of 和a couple of? the last of a series of competitions a new pair of football boots和a pair of new football boots有什么区别 a series