题目

 A warm thought suddenly came to me________ I might use the pocket money to buy some flowers for my mother’s birthday.     A. if            B. when         C. that          D. which 答案：C 在一个标准大气压下，对O℃的冰缓慢持续加热到全部变成100℃的水蒸气，下列所示的四个温度随时间变化的图象中正确的是    (     )