It is now clear that no such creatures as vampires have seen and none _____in the world.
A. was found
B. are found
C. have been found
D. have been found out
改正：题目少了一个been, 应该是It is now clear that no such creatures as vampires have been seen and none _____in the world.
C. have been found 应该是接前面，用完成时。find out1. 找出；发现；查明(真相等)：I'll find out her secret.我要弄清她的秘密。2. 查出…的罪行；揭发出；使受惩罚(或报应)：“Be sure your sin will find you out.”“你要相信你的罪行总要败露的。”3. 对(某弱处)起作用：This cold weather finds out my old wound.这个寒冷的天气使我的老伤发作了。4. 计算出
