下列离子方程式的书写正确的是（） A．SO2使酸性KMnO4褪色：5SO2 +

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问题选择题

下列离子方程式的书写正确的是（）

A．SO₂使酸性KMnO₄褪色：5SO₂ + 2MnO₄^－+ 2H₂O = 5SO₄²^－+ 2Mn²^＋+ 4H^＋

B．Fe(OH)₂与HNO₃溶液的反应：Fe(OH)₂ + 2H^＋= Fe²^＋+ 2H₂O

C．足量NaOH与磷酸二氢铵反应：OH^－+ NH₄^＋= NH₃·H₂O

D．将SO₂通入BaCl₂溶液中：SO₂ + H₂O + Ba²^＋= BaSO₃↓+ 2H^＋

答案

答案：A

选择题

看图片，将与图片相符合的句子的标号填在括号内。

A. He can read books now.

B. My grandmother cooked on a fire many years ago.

C. There weren't any aeroplanes two hundred years ago.

D. I had an old telephone three years ago.

选择题

---- One more question, Sir?

----Wait a minute. I ____ your questions for more than 30 minutes without a break.

Where is my cup?

A．have been answering

B．have answered

C．had answered

D．answered