问题补充:
—How often do I need to feed the fish?
-They food every day, or they will be hungry.
A. must give
B. mustn’t give
C. mustn’t be give.
D. must be given
答案:
A. must give
B. mustn’t give
C. mustn’t be give.
(答案→)D. must be given
解析:句意:你多久喂一次鱼?他们每天都必须被喂食,否则他们会饿。主语they指鱼,是动作的承受者,故用被动结构:be + done,含有情态动词的被动结构:情态动词+ be + done,结合句意及句子结构,故选D