Article in English: A green card gives you permanent residence in America while a Visa is temporary.  However, most people will get the work visa first, move to America, and then apply for a Green Card after some time.  You may want to hire a lawyer to help you navigate the different visas, or trust in your company HR department.  The Specialty Workers, or H1B Visa is designed for immigrants who wish to work in a specialized field.  Ask the company you are applying to if they will "sponsor you for an H1B."  Many companies will.  They will need to pay about $25,000 in lawyer costs, but if you are in demand, it may be worth it to them.  If you are unsure, you can ask them "if they will sponsor you after 6 months if things are working out well." The Temporary Skilled or Unskilled Workers, or H2B, Visa is provided for immigrants who want positions that are non-agricultural but are temporary in nature.  The Intracompany Transferees, or L1, Visa is for immigrants who will be working for a company that has operations in America. The employee must also be part of management or provide a specialized skill.  If you are working for a large company with offices in the USA, ask people in the USA office about this.  Employment-based Preference Visas are for those immigrants who are already employed, as this visa must be requested by the employer. Countries that are very friendly with the USA typically have better arrangements.  The E3 Visa is designed for citizens of Australia who are employed in America in a specialized capacity.  Canadian and Mexican citizens can apply for a TN Visa.  Special instructions for Canadians can be found here. Entrepreneurs should examine the Choose Between L1 or E Visa to Set Up a New Business in the U.S L1 and E Visas.  E2 Visas are well known because they allow you to get a Visa by simply investing money in a USA business, but note it does not have a path to a green card.

Summary in Chinese:
申请合适的工作签证。 要小心移民诈骗。 移民去一家公司工作有很多不同类型的签证。 某些国家的人可以申请特殊的签证。 如果你准备自己创业，申请的流程就不同了。