问题
填空题
Read and write. 读一读，按规律写数字。
1. one seven .
2. fifty-one seventy-one eighty-one .
3. twenty forty sixty .
4. thirty-five fifty-seven sixty-eight .
答案
1. three five nine 2. sixty-one ninety-one 3. thirty fifty seventy eighty 4. forty-six seventy-nine