这里应该填 a series of
a series of 一系列的；一连串的
eg:Boom!Boom!Boom!A series of explosions shook the valley.
轰!轰!轰!一连串爆破声震撼山谷.
a chain of 一系列,连串,连锁链
eg:Those you have sought to reach,whether they be in your family or elsewhere,are part of a chain of love that can extend through the generations.
那些你所想到的人,不管他们在你的家里或是其他什么地方,都是这条在几代人间延续的爱的链条上的一环.