several years he has been working like this.A. InB. AfterC. ForD. Since

问题补充：

several years he has been working like this.

A. In

B. After

C. For

D. Since

答案：

A. In

B. After

(答案→)C. For

D. Since

解析：本题的含义是他一直像这样工作了数年，for连接时间长度数年，故本题选C。