English verbs combine two things: a tense (present or past) and an aspect (simple, BE + -ING, or perfect with HAVE). Modal verbs then add the speaker's point of view: ability, obligation, probability, advice.
This page follows that logic, from the present to the modals, and points to the article that explores each form.
The present: simple or BE + -ING
The simple present states what is generally true or habitual; BE + -ING presents an action as in progress, temporary or unfinished.
I work from home. (a habit) · I'm working from home this week. (temporary)
The present perfect: linking past and present
HAVE + past participle looks at a past event from the present: its result, or a period that is not over.
I've lived here for ten years. (I still do)
The past: simple past, past continuous, past perfect
She was reading when I called. (an action in progress, interrupted)
Talking about the future
English has no dedicated future tense: will, BE going to, the present continuous and even the simple present each express a different relationship to what is coming.
The train leaves at 6pm. (a timetable, in the simple present)
Modal verbs
Can, may, must, shall, will and their past forms do not describe facts: they express how the speaker sees them.
You must leave. (I say so) · You have to leave. (the rules say so)
- Can and could: ability, permission, and possibility
- May and might: permission, probability, and politeness
- Must and have to: obligation, prohibition, and certainty
- Will and Would: volition, prediction, and habit
- Shall and should: authority, advice, and suggestion
- Ought to: moral advice and near-certainty
Beyond tenses
See also: English pronunciation and preparing for an English exam.