The comments which she made _______ marketing made her boss very happy. A.being concerned B.concerned C.concerning D.be concerned 答案:C18.依据下列说法来判断相应元素的金属性、非金属性强弱,不合理的是( )A.卤素单质Cl2、Br2、I2的氧化性强弱B.气态氢化物NH3、H2O、HF的稳定性C.碱金属单质Li、Na、K与水反应的剧烈程度D.1mol Na、Mg、Al分别与足量盐酸反应时失电子数的多少