14. athlete
15. end his basketball career 16. He has done more charity work, especially for poor Chinese teenagers.
17. 过去时+before/after+过去时(先后顺序)
before+从句（过去式），主句（过去完成时） after+从句（过去完成时）, 主句（过去式）
After I practiced… After practiced???? After practicing
18. When/While + doing sth 19. When+从句 he did sth(短动作，过去时), 主句he was doing sth/ he did sth(长动作,短动作)
20. While+从句 he was doing sth(长动作，过去进行时), 主句he was doing sth/ he did
sth(短动作,长动作)
21. When+从句 he does sth(短动作，现在时), 主句he will do sth (主将从现) 22. while 表转折，对比
23. 主句（现在完成时）since从句（过去时）
24. 肯定句 till=until “直到??为止”
否定句 not…until…“直到??才”
I did homework till/until 10 o’clock.
I didn’t go to bed until my father came back. “直到??才”
将来时+until+现在时 (主将从现)
过去时+until+过去时
25. 将来时+as soon as+现在时(主将从现) “一?就?” 过去时+ as soon as +过去时
