题干
—— Good evening. I _______ to see Miss Lisa.
—— Oh, good evening. I'm sorry, but she is not in.
A：have come
B：come
C：came
D：had come
答案(点此获取答案解析）
A
—— Good evening. I _______ to see Miss Lisa.
—— Oh, good evening. I'm sorry, but she is not in.
A：have come
B：come
C：came
D：had come
CH3COCH2Br＋HBr）来研究反应物浓度与反应速率的关系。反应速率v(Br2)通过测定溴的颜色消失所需的时间来确定。在一定温度下，获得如下实验数据：