Thanks to the joint efforts made by the leaders of China and the US over recent years mu

问题补充：

Thanks to the joint efforts made by the leaders of China and the US over recent years, mutually Sino-US relations have made remarkable progress.

A. adaptable

B. beneficial

C. relevant

D. convenient

答案：

A. adaptable

(答案→)B. beneficial

C. relevant

D. convenient

解析：

B句意：由于近年来中美两国领导人的共同努力，双边互惠的中美关系取得了长足的发展。beneficial意为“有益的”，符合句意。adaptable有适应能力的；relevant相关的；convenient方便的。