请教0209一道语法，多谢！

zerone

14. The seventeenth-century discovery    of life that are invisible to the naked eye was a dramatic one in the human history.
A. of forms
B. that forms
C. forms
D. forms are

答案C，我选A.
问题是主句的谓语动词是was，
选C的话主语是forms，不是冲突吗？选A，discovery作主语和was一致啊...

wycg

A是对的.

skykeeper

选A是对的...主语是discovery

zhangtian

a是对的啊

zx_nju

A, me too.