Proper first aid can save a seriously injured person，especially when he or she is bleeding heavily or .
A. has poisoned
B. was poisoned
C. has been poisoned
D. is poisoning
网友回答
A. has poisoned
B. was poisoned
(答案→)C. has been poisoned
D. is poisoning
解析：本题考查现在完成时。从语境可知，应当用现在完成时的被动语态。