Russia’s cutting off the gas supply raised a major concern to the European Union, a number of member states are increasingly dependent on one single supplier.
A. whose
B. that
C. where
D. which
网友回答
A. whose
B. that
(答案→)C. where
D. which
解析：句意：俄罗斯减少供给天然气供应使欧盟十分关注 ，而欧盟许多成员国对单一的供给的依赖正在增加。在定语从句中主谓宾完整，所以不选关系代词。故选C。
考点: 考查定语从句的关系词的用法。