12. __________________, many teenagers said they like table tennis. (surprise) 13. Christopher Columbus was one of the great __________________. (explore) 14. He came first in the chess __________________. (compete) 15. He is a good pearl __________________. (dive) 16. The United Nations __________________ is an international one. (organize) 17. Before the __________________ of special breathing equipment, man couldn’t swim __________________under water. (free) 18. Jacques Cousteau was a French __________________. (invent) 19. All __________________ must play fair. (compete) 20. The __________________ of the video games become very rich nowadays. (invent)