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。
China has a four-tier weather warning system, with red representing the most severe, followed by orange, yellow and blue.
好的目标价是根据一套合理的四因素估值法得出的，这四个因素给读者提供信息以确定目标价的准确性。
A good target price is based upon a reasonable set of four factors that provide the reader with information to determine the accuracy of the target price.
研究者给一些家庭送了一套游戏软件，另一些家庭则只有在完成了四个月的学习任务后才送游戏软件。
Researchers gave some families a game system; other families were promised a system when the four-month study ended.
应用推荐