【题目】In history，the Romany split into different groups and developed their own language， there are now approximately sixty varieties.
A. by which B. of which
C. by whom D. of whom
在线课程【答案】B
【解析】试题分析：考查定语从句。句意：在历史上，吉普赛人会分成不同的小组来发展他们的语言，所以现在有大约六十种语言。Of which指的是，在这些语言中，故选B项。
考点 : 考查定语从句