Question

 The professor said he could talk on _____ interested the audience.

A. any topic    B. which topic  

C. whichever topic   D. the topic he thought it

Answer 1

C

解析:

whichever已失去疑问含义，等于 anything that，表示强调； 而 which topic中 which保留疑问含义，译成"哪一个题目"，不符合句义。而A和D中缺少连词。