以前论坛里面有前辈讨论过的这道题:
106. In large doses, analgesics that work in the brain as antagonists to certain chemicals have caused psychological disturbances in patients, which may limit their potential to relieve severe pain.
(A) which may limit their potential to relieve
(B) which may limit their potential for relieving
(C) which may limit such analgesics’ potential to relieve
(D) an effect that may limit their potential to relieve
(E) an effect that may limit the potential of such analgesics for relieving