-How often are the Olympic Games held？ ---four years.A. EveryB. EachC. InD. For

问题补充：

---How often are the Olympic Games held？

---four years.

A. Every

B. Each

C. In

D. For

答案：

(答案→)A. Every

B. Each

C. In

D. For

解析：句意：--奥运会多久举办一次？--四年一次。分析：表示“每隔……”、“每……”，要用“every＋基数词＋复数名词”。这种结构中的every不能用each替代。在选项中只有every 符合题意。故选A