that these creatures are linked to a mon ancestor.
A. As is believed
B. What is believed
C. That is believed
D. It is believed
网友回答
A. As is believed
B. What is believed
C. That is believed
(答案→)D. It is believed
解析：考查句型：It is believed that…，据相信…,it 是形式主语，that引导的是真正的主语，句意：据相信这些生物和一个共同的祖先有联系。选D。