AwhoBwhichCwhatDthat

A. who

B. which

C. what

D. that

正确答案：B
29．答案为Bwhich引导定语从句代替前面的Ronald并做从句的主语Who只能代替人Ronald此处是名词并非人故不选Athat只引导限制性定语从句what引导名词性从句做动词的表语和宾语