Professor James will give us _______________ lecture on western culture but when and where _________ (not,decide) yet.
问题描述：
Professor James will give us _______________ lecture on western culture but when and where _________ (not,decide) yet.
主要是第二空不会填啊
答
a has not been decided.第二空主要是因为后面有yet这个完成时的标志词.