题目

下列运算中正确的是（  ）A．3ab－2ab＝1B．x4·x2＝x6 C．(x2)3＝x5 D．3x2÷x＝2x 答案：B解析:略 －I came to your office yesterday morning, but nobody was in． －Oh, we ________ a meeting in the meeting room． [　　] A．have had B．had C．were having D．had had