题目

— Jack, do you know the answer ______  this question? It’s too difficult for me. — Sorry, I don’t know. You can ask Jim for help. He is good at math.A. with         B. to           C. for                 D. at 答案：B关于蜡烛在空气中燃烧，下列叙述不正确的是A.有氧气参加的反应B.只发生化学变化C.既发生物理变化又发生化学变化D.生成两种新物质