1 I met my boss on my way home yesterday.
2 I want you to promise me one thing.
3 He has been to Africa three times .( 好像多了for,如果确定不错,那就是放在three 的前面,即 He has been to Africa for three times .）
4 She was writing a letter when I called .
my boss,I,on my way home,meet,yesterday
want,me,promise,one thing,I,to,you
be,he,Africa,for,to,three,times
a letter,she,call,I,write,when