问题
单项选择题
In our own galaxy, the Milky Way, there are perhaps 200 billion stars, a small part of them probably have planets on which life is feasible.
A．a small fraction in which
B．a small fraction of which
C．a small fraction which
D．which a fraction of
答案
参考答案：B
解析：结构应用。英语的定语从句(不论是限定性或非限定性)中，当关系代词作介词宾语时，介词前置，其中whom指人，which指物；而介词of表示整体中的一部分，比用in准确，所以B为答案。