you have to do the job, you should try your best to do it well even though it may be ver

you have to do the job, you should try your best to do it well even though it may be very difficult for you.
A. Since
B. While
C. Unless
D. Though

(答案→)A. SinceB. WhileC. UnlessD. Though解析：A 考察连词。句义：既然你要做这份工作，就尽力去做。Since既然，while然而；unless除非；though尽管；根据句义说明A正确。

就是这个解释