The future continuous tense is used to refer to actions that will be in progress at or around a specific point in time in the future. This point can be implied or expressed with a time expression or a clause with a verb in the present simple tense:
The future perfect continuous tense is used to express events that will start before a point in time in the future (or have already started) and will still be in progress at that point:
By tomorrow, it will have been raining for four days.
Soon, he'll have been running for 4 hours.
The future perfect tense is used to express that an action will be completed before a point in time in the future (any time up to that point). This point can be implied or expressed with a time expression or a clause with a verb in the present simple tense:
The past continuous tense is used to refer to actions that were in progress at or around a specific point in time in the past. This point can be implied or expressed with a time expression or a clause with a verb in the past simple tense:
The past perfect continuous tense is used to express that an action started before a point in time in the past and that it was still in progress or it had just stopped. This point can be implied or expressed with a time expression or a clause with a verb in the past simple tense:
The past perfect tense is used to express that an action was completed before a point in time in the past. This point can be implied or expressed with a time expression or a clause with a verb in the past simple tense:
The past simple tense is used for actions which are completed at a definite point in time in the past. This point can be implied or expressed with a time expression or a clause:
The past simple is used to refer to a point in the past at which another event was in progress, had been completed or had been going on for some time. The past simple thus serves as a time marker in subordinate time clauses within complex sentences, where the main clause is in the past continuous, past perfect or past perfect continuous tense:
