实现下列变化，必须加入氧化剂或还原剂的是
A．NO2→HNO3
B．NH4＋→NH3
C．Cl2 →HClO
D．NH3→NO
答案：D
Don’t leave your books on the table．Please _______．
A．take away it
B．take them away
C．take away them
D．take it away
三位二进制数对应一位八进制数
