1. C 阶段，时期　a stage of development
2. C （月亮、行星的）位相，盈亏　any of a fixed number of changes in the appearance of the moon or a planet as seen from the Earth at different times during their orbit
3. C （问题等的）方面　part of aspect

　alter the ～　改变相位
　begin〔enter, go through〕 a ～　开始〔进入，经过〕一个阶段
　pass through three ～s　经过三阶段
　closing〔initial〕 ～　最后〔最初〕阶段
　crucial ～　关键时期
　final ～　最后形势
　new ～　新阶段
　essential ～　基本方面
　opening ～　开始阶段
　another ～　另一阶段
　the theoretical ～s　理论方面
　～ difference　相位差
　from ～ to ～ during this stage　这一阶段中的各个时期
　in ～　同相地，协调地
　in ～ with　与…同相位
　in every ～　在每一方面
　out of ～　异相地，不同相地，不协调地
　opposite in ～　反相，相位相反
　～ of the campaign　战斗的阶段
　～s of the problem　问题的各方面
　～ of the research　研究阶段

　It was a very important phase of history.　它是一个非常重要的历史阶段。
　There was a new dangerous phase between each other.　双方的关系进入到一种危险的状态。
　The phases of the moon include the new and the full moon.　月相包括新月和满月。

 ♣ in phase
　〈物理〉同相　working or going together (with another or each other)
　The camshaft rotates in phase with the crankshaft, but at half its speed.　凸轮轴和曲轴协调旋转，但速度仅是曲轴的一半。
 ♣ out of phase
　〈物理〉异相　not working or going together (with another or each other)
　The carrier wave has got out of phase with the signal wave.　载波同信号波是异相的。

 ♣ phase, angle, aspect, side
　参见aspect条。
 ♣ phase, stage
　这两个词都可指发展的阶段或时期，但stage除了与介词of连用以外还可与at连用；另外，侧重于外观变化时用phase，不用stage.

　vt.　分阶段计划〔安排〕plan or arrange in separate phases

　～ down　逐步减少
　～ in　逐步采用
　～ out　逐步淘汰

　The new educational policy will be phased over the next several years.　新的教育政策将在未来几年内分阶段实施。

 ♣ phase down　(v.+adv.)
　逐步减少　lessen gradually
　The program to phase down waste in natural sources is progressing successfully in the country.　逐步减少自然能源的浪费正在这个国家顺利进行。
 ♣ phase in　(v.+adv.)
　逐步采用　introduce (sth) in stages or gradually
　We should phase in the new working plans.　我们应逐步采用新的工作计划。
　The company has phased in a series of new production plans.　这家公司已采用了一系列新的生产计划。
 ♣ phase out　(v.+adv.)
　逐步淘汰，逐步结束　stop or remove (sth) in stages or gradually
　The machine has been phased out.　这种机器早已过时了。
　The factory has already phased out a batch of production equipment.　这家工厂已经淘汰了一批生产设备。

　［同义词］ n. condition, degree, level, step, view
　［词源］希腊语phasis（阶段）