— I haven’t got the reference book yet but I’ll have a test on the subject next month. —

问题补充：

— I haven’t got the reference book yet, but I’ll have a test on the subject next month.

— Don’t worry. You have it by Friday.

A. could

B. shall

C. may

D. must

答案：

A. could

(答案→)B. shall

C. may

D. must

解析：

这题考查情态动词shall的用法，shall可以用于第二、三人称表示“允诺，警告，命令”，这句话是表示允诺，句意是：别担心，你星期五可以得到它。选B。