The new shop announced that the first to purchase goods on the opening day get a big prize

问题补充：

The new shop announced that the first to purchase goods on the opening day get a big prize.

A. will

B. shall

C. must

D. might

答案：

A. will

(答案→)B. shall

C. must

D. might

解析：试题分析:句意,这家新店宣布在开业那天第一个买到货物的人会得到一个大奖.will由于将来时态多表示将来自然发生的事情.shall用于第二三人称时,其意义相当于一个情态动词, 表示一种承诺、命令、要求的含义.must用于肯定句表示必须一定.might为may的过去时态,意思为可以.故选B.