问题补充:
Every means, but none proved.
A. have tried; a success
B. have been tried; successful
C. has tried; to be successful
D. has been tried; successful
答案:
A. have tried; a success
B. have been tried; successful
C. has tried; to be successful
(答案→)D. has been tried; successful
解析:考查主谓一致:means是单复数同形的名词,单复数取决于修饰词,这句话means用every修饰,说明是单数,谓语用单数,而且means和try是被动关系,用has been tried,第二空的prove是连系动词,后面接形容词做表语。句意:每种办法都被尝试过了,但没有一个证明是成功的。选D。