摘自:美国移民局网站

Employment - Working for Immigration劳工移民
classification includes:分类包括
" Aliens with at least two years of experience as skilled workers；至少有两年工作经验的外国技术工人
" Professionals with a baccalaureate degree; and 拥有英美学士学位的专业人员，和
" Other workers with less than two years experience, such as an unskilled worker who can perform labor for which qualified workers are not available in the United States. 其他工人，至少两年工作经历，例如一个非技术工人，能够参加一种劳动，这种劳动在美国国内没有可利用的工人资源

Skilled worker 技术工人positions are not seasonal or temporary and require at least two years of experience or training. 职位不能是季节性的或临时性的，并且有至少两年的教育/培训经验。The training requirement may be met through relevant post-secondary education. 要求是高中教育后的专业培训经验。The Form ETA-750 (Labor Certification) states the job requirements, which determine whether a job is skilled or unskilled. 表ETA-750（劳动证明）列出了有关工作是技术工作还是非技术工作。For more information, please see the Department of Labor's Employment and Training Administration Website.更多信息请参阅劳工就业、培训部网站。

Professionals 专业人员must hold a U.S. baccalaureate degree or foreign equivalent degree that is normally required for the profession. 一定要有美国学士学位或外国同等学士学位的专业人员。Education and experience may not be substituted for the degree.教育和工作经验不能替代学士学位。

Other workers 其他工人are in positions that require less than two years of higher education, training, or experience. 有至少两年或以上的教育、培训、工作经验。However, due to the long backlog, a petitioner could expect to wait many years before being granted a visa under this category. 在这种类别中，由于有很多的未处理案件，所以申请人要等待很长的时间才能获得一个签证。See How Do I Get an Immigrant Visa Number? for more information.我如何获得一个移民签证号码请看更多信息。
Application Procedures申请过程
Your employer must file a BCIS Form I-140 at the BCIS Regional Service Center that serves the area where you will work. All I-140 EB-3 petitions must include a labor certification and a permanent, full-time job offer. There are no exceptions. Additional guidance relating to Department of Labor requirements is found at the Department of Labor's Employment and Training Administration Website.
Forms are available by calling 1-800-870-3676, or by submitting a request through our forms by mail system. For further information on filing fees, please see BCIS filing fees, fee waiver request procedures, and the BCIS fee waiver policy memo. Please see our BCIS field offices home page for more information on BCIS offices.

Employment Based Immigrant Visas 劳工移民签证
" Labor Certification 劳动证明
" Extraordinary, Exceptional Ability & National Interest Waivers国家有兴趣放弃的有非常的、优越的能力
" Live-in Domestic 生活在本国

Labor Certification: 劳动证明
Company sponsorship required after extensive demonstration of the inability to find a legal resident or citizen to perform the required job. 公司要证明无能力找到一个合法居民或公民从事这个需要的工作。

Extraordinary, Exceptional & National Interest Waiver : 国家有兴趣放弃的有非常的、优越的能力
The Director, United States Employment Service, has determined that there are not sufficient United States workers who are able, willing, qualified, and available for certain occupations, and that the wages and working conditions of United States workers similarly employed will not be adversely　affected by the employment of aliens.
美国劳工服务中心坚定（一件事）：雇主在美国找不到足够、有能力的、甘心情愿的、有资格的、可利用的工人，从事某种（特定）职业，并且提供这样的工资报酬和工作条件－与美国工人相比，雇用外国人不会遭到反对和没有负面影响。

Live In Domestic Employee: 生活在本国
Labor certification is required for the hiring of a "Nanny" to perform full time domestic-type employment.在国内，雇主雇佣全职员工需要提供劳动证明。