1. three hundred"and"twenty-one
2. one half / one-half / a half
3. four fifths / four-fifths
4. three forty-five / fifteen (minutes) to four / a quarter to four
5. five twenty-five / twenty-five (minutes) past five
6. nineteen hundred"and"five / nineteen o five
7. ninety-six point zero five
8. twenty-three percent
9. May 10th / May the tenth
10. No. 8
11. in the 1930s / in the nineteen thirties
12. the twenty-first lesson / Lesson 21 / Lesson Twenty-one
【解析】参考教材 第四章 数词 3.数词的应用