our opinions should___ factsa,base on b.be based on c.base upon d.ba based
问题描述：
our opinions should___ facts
a,base on b.be based on c.base upon d.ba based
答
B,be based on,以。。。为依据，用被动语态
答
b
答
b.be based on
base on 词组,意思是以...为依据
这里要用被动语态