Please do not feed the fish; they die if they eat too much.A. shallB. mustC. needD. may

问题补充：

Please do not feed the fish; they die if they eat too much.

A. shall

B. must

C. need

D. may

答案：

A. shall

B. must

C. need

(答案→)D. may

解析：考查情态动词。Shall将要；表示允诺，强制，命令；must必须，一定;need需要；may也许；句意：请不要喂那些鱼了。如果它们吃太多，也许会死掉的。故D正确。