第35题: [单项选择]The phrase "once in a blue moon" in last line refers to ______. A. all at once B. once for a long time C. once in a while D. once and for all 参考答案:B 答案解析:[解析] 语义理解题。本题考的是习语。习语“once in a blue moon”的意思是“千载难逢地”,与“once for a long time”基本同义。在阅读理解中做语义题一定要结合习语所