The J2EE architecture is based on a four-tier layer model that characterizes a J2EE-compliant enterprise application.

J2EE体系结构是以一个4层模型为基础而建立的，该模型刻划了J2EE兼容的企业应用程序的特征。

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China has a four-tier weather warning system, with red representing the most severe, followed by orange, yellow and blue.

中国有一套四个等级的天气预警系统，红色代表情况最为严重，其次是橙色、黄色和蓝色。

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China a has a four-tier color-coded warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.

中国对极端天气有一套四级预警系统，用四种颜色分别表示等级不同的预警，其中红色为最，其次是橙色、黄色和蓝色。 。

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At the same time, four Tier-Three countries from last year were upgraded in recognition of their anti-trafficking efforts Algeria,Moldova,Oman and Qatar.

VOA: standard.2009.06.16

Under the four-tier system, teachers will be rated exemplary, proficient, developing or below standard.

WSJ: Conn. Joining Teacher Trend

Teachers marked "ineffective" the lowest rating in a new four-tier system would get a second opinion by a third-party "validator" chosen by the union and the Department of Education.

WSJ: Teacher Evaluation Deal Reached

Its Arrow 2 interceptor missile (developed with Boeing) will soon be joined by the Arrow 3 to form part of a four-tier territorial and theatre defence against every kind of rocket attack.

ECONOMIST: Aerospace in Israel