题目

用化学用语填空： (1)镁         ；(2) 2个氮气分子            ；(3)5个硫酸根离子          ； (4)甲烷            ；(5)+6价的硫元素              ； (6)由Fe 3+和OH— 构成的氢氧化铁               。 答案：⑴Mg   ⑵2N2   ⑶5SO42—   ⑷CH4   ⑸       ⑹ Fe(OH)3Why didn't you make me a telephone call yesterday? I ________ about it. [　　] A．should be toldB．ought to have been told C．should have toldD．ought to be told