由于保安事件危险性升高而应在一段时间内保持适当的附加防范性保安措施的等级称为保安等级()。

----- A heavy snow hit most of the parts of China in January,2008.

----- ____________ terrible news!

In order to set up her research programme, Shona got____.

Students want to keep the Self-Access Centre because____.

在处理工商行政管理机关之间管辖权争执时，普遍遵循的原则是()。

Your donations can _____ poor children ____ food and a chance to study.

压力容器的每个部件都必须有足够的( )，并且在应力集中的地方，如筒体上的开孔处，必要时还要进行适当的补强。

Shona says that in her questionnaire her aim was____.

As early as in the development of agriculture,men discovered how to make alcoholic drinks from grapes and corn.

一国某一时期的出口总额超过进口总额时，称为()。