题目

阅读理解Inthe fight against the novel coronavirus, scientific progress has proven to bean important factor in helping win the war against this deadly disease. Thanksto the efforts of scientists and researchers in China, major medical andtechnological breakthroughs have been made, bringing us closer to victory. SinceChinese scientists discovered the genetic structure of the novel coronavirus,researchers both in China and around the world have been working tirelessly. Notonly have they been working toward developing a vaccine (疫苗) to prevent the spread of the virus, but they are also sea Great changes have taken place in that school. It is no longer _____it was 20 years ago, ______it was so poorly equipped. A.  What ;when      B. that; which    C.  what; which     D. which; that