They will pay a visit to Europe in a couple of years _____ they have enough money.

A．for fear that

B．on condition that

C．even though

D．as well as

一个征税对象同时适用几个等级税率形式的是( )。

A．定额税率

B．比例税率

C．超额累进税率

D．全额累进税率