great changes have taken place in that school.it is no longer---it was 20 years ago,when it was so porly equipped.
---上填what that which when 之中的那个？ 为什么这么填？
參考答案:what.
因为这里what当成了两个成分，全面一句话里is的宾语和后面一句话的主语。这句话强调的是地方，不是时间。
这里全部句子应该是：It is no longer the place that it was 20 years ago.
