用元素符号、离子符号、化学式或名称填空：

(1)2个氮原子              ，

(2)5个钾离子              ，

(3)1个氧分子              ，

(4)5个氮分子               ，

(5)7个氯离子             ，

(6)8个水分子              ，

(7)I           ，

(8)3个碳酸根离子             。

I had expected to come over to see you last night, but someone ______ and I couldn’t get away.

A．called

B．had called

C．would call

D．would have called