2012年1月1日起实施的《中华人民共和国车船税法》将车船税分7个梯度按照排量进

国债发行时已确定利率基数，但此基数可随市场物价水平上涨而上浮的国债称为( )。

A．自由国债

B．固定利率国债

C．浮动利率国债

D．保值国债

“Did you get a job?” “No, I ______, but it’s no use.”

A．expected

B．tried to

C．managed to

D．planned

中性突变

Atmosphere laden with coal dust or grain dust caused by loading these cargoes（）.

A.require loading operations to be shut down until the atmosphere clears

B.are toxic to human life

C.are subject to spontaneous combustion

D.may be explosive in some concentrations