AN explorer was caught by a tribe (部落) whose chief (首领) decided that the man should die. The chief was a very logical (逻辑性强的) man and gave the explorer a choice. The explorer was to make a single statement. If it were true, he would be thrown over a high cliff (悬崖). If it were false, he would be fed to lions. What statement did the clever explorer make that forced (迫使) the chief to let him go?