When---（build）our new school library hasn't decide

1 When TO BUILD （build）our new school library hasn't been decided yet
--------when + 动词不定式 做主语

2 He was told that the exhibition WOULD BE HELD （hold）the next week.
---------主句是过去式+ 从句部分（以後要发生的事情,谓语动词是过去将来时）

原因已经解释了,呵呵.
再问： 帮我翻译个句子吧:Each piano was painted by an artist who lived in Canada but was born in one of the 41 counties.
再答： 每一架钢琴的画都由一位画家画出，这些画家都住在加拿大，但他们的出生地是四十一个不同的国家。