The future perfect tense is used to show a time difference between two future events. As with all perfect tenses, we cannot use the future perfect tense to talk about only one event or instance. It must be used to compare two different events or instances.
The future perfect tense is formed using:
subject + will + have + past participle
Since we are comparing two different events or instances, we often use time clauses in the future perfect tense.
| Earlier Event | Later Event |
| We will have lived in Europe for five years | by the end of next month. |
| I'll have finished reading the book | by the time the movie comes out. |
| It'll have been four hours of waiting | when she finally arrives. |
| They will have eaten lunch | by the time the field trip is over. |
The future perfect is always used to describe the earlier event. We can talk about the later event by using a time clause in the simple present or by using a time phrase.
| We will have lived in Europe for five years | by the end of next month. |
| We will have lived in Europe for five years | by the time we move to South Africa. |
Exercise
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