by the end of last year,another new gymnasium ___ in beijingBy the end of last year,another new gymnasium ___ in beijinga.would be completed b.has been completed c.had been completed选C 为何选过完?

问题描述:

by the end of last year,another new gymnasium ___ in beijing
By the end of last year,another new gymnasium ___ in beijinga.would be completed b.has been completed c.had been completed
选C 为何选过完?

a,would 是虚拟语气,或者will的过去时,但句意是说去年年底,体育馆完成,所以would不合适,而不是去年年底,体育馆将要完成,别扭吧。
b与c的区别就是 时态了,b是has 就是一般现在完成时,但是时间是去年,所以就是过去完成时。
所以就选C

过去完成时嘛
last year 是过去日,last year 之前自然是过去完成时了

句意:去年年底,另一个新的体育馆在北京落成了.
时间是“By the end of last year”,首先可以判断是过去时,又因为已经建完了,动作已经完成,所以是完成时.因此,选C,过去完成时.