题目

David felt very happy. ___, it was his first time to have a party in our class for him.A. At least B. After all C. At once D. At all 答案：【答案】B【解析】句意：戴维感到非常高兴。毕竟，这是他第一次在我们班为他举办一个聚会。A. At least至少；B. After all毕竟；C. At once立刻；D. At all，not…at all，一点也不。根据语义可知是“毕竟”之意。故选：B。下列物质中，不与NaOH溶液反应的是　　　[　　] A．二氧化碳　　　B．碳单质　　　C．二氧化硅　　　D．氯气