英语时态是动词用来表示动作发生时间和状态的语法形式。英语主要有12种基本时态，它们由两个维度组成：时间维度包括过去、现在和将来；状态维度包括简单、进行、完成和完成进行四种形式。这两个维度的组合构成了英语的时态系统。
Present tenses include four basic forms. Simple present uses do or does to express habitual actions or objective facts, like 'I work every day'. Present continuous uses am, is, or are plus the -ing form to show ongoing actions, like 'I am working now'. Present perfect uses have or has plus the past participle to indicate completed actions, like 'I have worked'. Present perfect continuous uses have or has been plus the -ing form to emphasize the duration of actions.
Past tenses describe actions that happened before now. Simple past uses 'did' to express completed actions, like 'I worked yesterday'. Past continuous uses 'was' or 'were' plus the -ing form for ongoing past actions, like 'I was working at 3pm'. Past perfect uses 'had' plus the past participle for actions completed before another past action, like 'I had worked before he arrived'. Past perfect continuous uses 'had been' plus the -ing form to emphasize duration before a past point.
Future tenses express actions that will happen after now. Simple future uses 'will' plus the base form to express future actions, like 'I will work tomorrow'. Future continuous uses 'will be' plus the -ing form for ongoing future actions, like 'I will be working at 3pm tomorrow'. Future perfect uses 'will have' plus the past participle for actions that will be completed before a future point, like 'I will have worked by then'. Future perfect continuous uses 'will have been' plus the -ing form to emphasize duration up to a future point.
English has 12 basic tenses formed by combining three time dimensions with four aspects. The time dimensions are past, present, and future. The four aspects are simple for basic actions, continuous for ongoing actions, perfect for completed actions, and perfect continuous for emphasizing duration. By combining these elements, we get all 12 tenses: present simple, present continuous, present perfect, present perfect continuous, and similarly for past and future. Understanding this systematic structure helps learners master English tenses more effectively.