--Mom guess what? I’ve won the 1st prize!---This­­a celebration! Let’s go to prep

问题补充：

--Mom, guess what? I’ve won the 1st prize!

---This­­a celebration! Let’s go to prepare a party．

A. helps out

B. works out

C. calls for

D. pays for

答案：

A. helps out

B. works out

(答案→)C. calls for

D. pays for

解析：考查动词短语辨析。A帮助脱离困境；B锻炼；计算除；C要求，需要；D付钱；句意：—妈妈，猜猜发生什么事情了？我们赢得了第一名。—这要好好庆祝啊！让我们准备一个聚会吧！根据句意说明C正确。