问题补充：
We have to learn words this term..
A. twenty-three thousand and eight hundred and thirteen
B. twenty-three thousand and eight hundred thirteen
C. twenty-three thousand eight hundred and thirteen
D. two three thousand eight hundred and thirteen
答案：
A. twenty-three thousand and eight hundred and thirteen
B. twenty-three thousand and eight hundred thirteen
(答案→)C. twenty-three thousand eight hundred and thirteen
D. two three thousand eight hundred and thirteen
解析：句意：我们这个学期将不得不学习两万三千八百一十三个单词。在英语中数字的表达从左到右每隔三个字母为一个单位，两万三用twenty-three thousand来表示，八百一十三用eight hundred and thirteen来表示，即在百和十之间加连词and，故选C。
