单项选择题
A．He has learned a lot from his own mistakes. B．He is quite experienced in taming wild dogs. C．He finds reward more effective than punishment. D．He thinks it important to master basic training skills.
A．He’d like a piece of pie. B．He’d rather stay in the warm room. C．He’d like some coffee. D．He’s just had dinner with his friends.
A．It helps improve their safety. B．It helps them fight their predators. C．It allows them to swim faster. D．It allows them to avoid twists and turns.