ThereareseveralresearchcentersinChina

问题详情：

There are several research centers in China ________ a certain disease called Bird Flu is being studied.

A. which        B. where            C. when                   D. what

【回答】

B. 因为先行词是research centers并在定语从句中作状语，所以用where。

知识点：定语从句

题型：选择题