President Obama held talks with Chinese President Hu Jintao in Beijing economic recovery

问题补充：

President Obama held talks with Chinese President Hu Jintao in Beijing, economic recovery, climate change and stopping the spread of nuclear weapons.

A. which was discussed

B. in which they-discussed

C. when they discussed

D. which discussed

答案：

A. which was discussed

(答案→)B. in which they-discussed

C. when they discussed

D. which discussed

解析：考查非限制性定语从句。句意“奥巴马总统和胡锦涛主席在北京举行了多次谈话，谈话中，他们讨论了经济复苏，气候变化和阻止核武器扩散等问题。”先行词是talks，从句缺少地点状语，in which相当于where。故选B。