Tenses & Timelines: Future Perfect
April 4, 2019
Written by Douglas Shaw
The future perfect tense is used to demonstrate an action which is promised to be done by a certain time in the future:
To form the future perfect, we use time expressions (by the time, by then, by the year XXXX, by March XX);
Subject + shall/will + have + verb in the past participle
Sometimes, you can use the future perfect tense and the simple future tense interchangeably. In these two sentences, there is no real difference in meaning because the word before makes the sequence of events clear:
- Linda will leave before you get there.
- Linda will have left before you get there.
But without prepositions such as before or by the time that make the sequence of events clear, you need to use the future perfect to show what happened first.
- At eight o’clock Linda will leave. (This means that Linda will wait until 8 o’clock to leave.)
- At eight o’clock Linda will have left. (This means Linda will leave before 8 o’clock.)