Ⅰ.单项填空
1．________every member has arrived，let's get down to________the plan for the next five years.
A．Now that；work out B．Because；work out
C．Since；working out D．For；working out
【解析】 句意：既然每一个人都来了，让我们开始制订我们的下一个五年计划。get down to开始做……，to为介词，故其后接动名词形式，可排除A、B项；for不能位于句首引导从句。
【答案】 C
