Do you know ______actor, Kim Soo-hyun—Yes, I do. He is my favorite Korean actor.

Paris (巴黎) is one of ______ cities in the world.

It puzzles the scientists _____ some mammals produce their young _____ others lay eggs

You can’t ___ possession of the house until all the papers have been signed.

do da Vinci ______ a scientist, if he had not been so skilled in other areas.