初二英语单选,同义词换:atfirstthemovieisnotsointeresting
Atfirstthemovieisnotsointeresting.
要替换掉atfirst.
A.ForthefirsttimeB.Intheend
C.InthebeginningD.Oneminute
老师给的答案是C,但我在有道词典上查A和C都是词组,应该是什么,有什么区别?