题目

 It often makes you don't know how to_____call a newly known person, and people also become more and more sensitive in calling each other. A. hopelessly B. appropriately C. needlessly D. constantly 答案：B“金、银、铜、铁、锡”俗称五金。在这五种金属中，金属活动性最强的是  [     ]A．铁 B．金 C．银 D．铜