— My cousin is good at all his subjects at school, but he never ________.
— What a ________ boy! We should learn from him.
A:gets off; thoughtful
B:takes off; energetic
C:shows off; modest
D:puts off; curious
阳离子
K+ Ba2+ Fe2+ Al3+ Fe3+ Mg2+
阴离子
OH﹣ HCO3﹣ CO32﹣ Cl﹣ NO3﹣ SO42﹣
若向原溶液中加入足量的盐酸,有无色气体生成.经分析反应后溶液中阴离子的种类没有变化.
①凡是法律所禁止的事情,我们坚决不做
②触犯法律,会受到法律的追究
③法律是解决纠纷的唯一最好的方式
④任何违法行为都要承担相应的法律责任,在法律面前人人平等
设fx为定义在R上的奇函数,当x≥0时,fx=2x+2x+m(m为常数),则f-1( )