What is the main clause of this sentence?

He pledged the car as collateral.

Her hair type is very soft, and it feels good to touch.

My father is the head of our household.

The master of ceremonies is my important friend.

The master of ceremonies is my dear friend.

The OP's opinion is always helpful.

He is the founder of this art association.

I go to church with my family on the Sabbath.

He is the owner of that company.