The simple past tense of shut is shut. This means that the past tense form of the verb ‘shut’ remains the same as its base form.
For example:
- She shut the door quietly.
- They shut the windows before leaving the house.
In these sentences, ‘shut’ is used to describe an action that was completed in the past. The verb ‘shut’ is irregular, which is why its past tense form does not change.