Nobody but us the secret.A. knowB. knowsC. have knownD. is known

问题补充：

Nobody but us the secret.

A. know

B. knows

C. have known

D. is known

答案：

A. know

(答案→)B. knows

C. have known

D. is known

解析：句意：除我们之外没有人知道这个秘密。由but(除了)连接的两个主语时，谓语动词要与前一个主语保持一致，nobody是不定代词，谓语动词用单数，而A&C都是复数，故排除；而D项是被动，在句子需要一个主动式，故答案选B。