Mr. Teranushi is an old friend of mine.

The temple priest offers prayers at the temple every day.

Mr. Teranushi is my best friend.

Every morning, I recite the Lord's Prayer.

I completely disagree with the OP's opinion.

What is the main clause of this sentence?

The uploader's video is very interesting.

The OP's opinion is always helpful.

The Devonian period was a very important time in the history of the Earth.

In geomorphology, an antidune is a special type of sand dune that forms on the downstream side of a water flow.