问题补充：
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：
A. Now that...carry
B. Because...carry
(答案→)C. Since...carrying
D. Now...putting
解析：get down to doing sth. to为介词，开始认真做某事
