What is an example of the pluperfect tense?

The pluperfect tense describes an action that was completed before another action in the past.

Here's an example:

"I had finished my homework before my friends arrived."

* "Had finished" is the pluperfect tense of the verb "to finish."

* This sentence indicates that the speaker completed their homework (the first action) before their friends arrived (the second action).

Here are some other examples:

* "She had eaten dinner by the time her parents got home."

* "They had already left the party when the music started."

* "He had been studying for hours before he finally took the test."

The pluperfect tense is often used to show a cause-and-effect relationship between two past actions.