happen 指事先无计划、偶然地发生take place 指事先安排、计划的事情

　break out 爆发，强调突然发生

　事故是如何发生的？_________________________________________

　婚礼何时举行？___________________________________________

　昨晚失火了。__________________________________________

4. in the future _______________ in future ___________________

5. 多达_________ 6. 确定，确信_________________

7. be used to do _______________ used to __________________

　be used to __________________