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

A．must

B．will

C．shall

D．need

玻璃体积血是由于（）

A.玻璃体本身血管破裂

B.睫状体、视网膜或脉络膜的血管损伤引起

C.前房角挫伤

D.房角后退

E.玻璃体变性