First, the meaning is different.
1, Work: Work, occupation, responsibility, work content, work.
2. Work: operation, working method, mine, roadway and working area (mine or quarry).
Second, the usage is different.
1, Work: The basic meaning of work is "work, labor, homework", which generally refers to uncountable time, refers to the specific work modified by indefinite article A, and can be interpreted as occupation, post, work, achievement, product, handicraft industry, trade, special research, behavior, function, merit, etc. This is an uncountable noun. When used as a subject, the predicate verb must be singular.
2. Work: basically refers to "purposefully engaging in physical or mental work", which can mean that people are working and doing things, or that people are studying, researching and delving into a certain thing or discipline, or that the machine runs and starts smoothly, the plan goes smoothly, the effectiveness of drugs and so on.
Third, the emphasis is different.
1, Work: Work refers to what you need to do, that is, the workload. Represents a certain amount of work.
2. Being at work: Being at work refers to the state of work, and only the state that you are doing this work indicates action.