题目

Maria has _________ trouble _________ math, so she often asks her math teacher for help.    A. much; understanding       B. no; to understanding  C. many; understanding 答案：A小明用凉水冷却滚烫的鸡蛋，是在利用水________大的热学特性，此时鸡蛋内能是通过________的方式改变的．如果冷却用水的质量为1千克，温度上升了10℃，则水吸收的热量为________焦．〔c水=4.2×103焦耳/（千克?℃）〕