Without facts,we can’t form a worthwhile opinion for we need to have factual knowledge       

our thinking. [ ]

A.which to be based on

B.which to based on

C.on which to base

D.to which to be based

警衔等级的设置是等衔制度的核心，没有( )等十三级。

A．四

B．五

C．六

D．七