________ the plan has been made, let's get down to ________ it out．

________ the plan has been made, let's get down to ________ it out．

A.Now that; carry

B.Because; carry

C.Since; carrying

D.Now; putting

答案及解析： C

解析：

get down to(doing)sth．表示“开始认真做事”，now(that), since均表示“既然，由于”。