Present perfect:

I have finished my homework.She has not traveled abroad before.They have already eaten dinner.John has lost his keys somewhere.The company has announced a new product.

Past perfect:

She had already left the party when I arrived.By the time I woke up, he had already gone to work.We had finished our project before the deadline.The train had already left when we arrived at the station.She had never seen such a beautiful sunset before.

Future perfect:

By next year, I will have completed my degree.By the time she arrives, we will have finished setting up the decorations.They will have experienced many adventures by the end of their travels.The construction work will have been completed by the time the new school year starts.By the time we reach the top of the mountain, the sun will have already set.