These are all words for the work that sb does in return for payment, especially over a long period of time. 以上各词均指有报酬的工作，尤指长期从事的职业。
work the job that sb does, especially in order to earn money指工作、职业：◆It's very difficult to find work at the moment.目前很难找到工作。
employment(ratherformal) work, especially when it is done to earn money; the state of being employed or the situation in which people have work指工作、职业、受雇、就业：◆Only half the people here are in paid employment.这儿只有一半的人有拿工资的工作。
career the job or series of jobs that sb has in a particular area of work, usually involving more responsibility as time passes指生涯、职业：◆He had a very distinguished career in the Foreign Office.他在外交部有过一段光辉的事业。
profession a type of job that needs special training or skill, especially one that needs a high level of education指需要专门技能（尤其是较高教育水平）的职业、专业：◆He hopes to enter the medical profession.他希望能从事医务工作。NOTEThe profession is all the people who work in a particular profession. * the profession 统称某专业的人、同行、同业：◆the legal profession法律界The professions are the traditional jobs that need a high level of education and training, such as being a doctor or lawyer. * the professions 统称需要较高教育水平的传统职业，如医生、律师等。
occupation(ratherformal) a job or profession指工作、职业：◆Please state your name, age, and occupation.请写明姓名、年龄和职业。
trade a job, especially one that involves working with your hands and requires special training and skills指行业，尤指手工职业、手艺、行当：◆Carpentry is a highly skilled trade.木工是需要纯熟技巧的职业。