Question

麻烦解释一下

Either you or the headmaster ___ the prizes to those gifted students at the meeting.
A.is handing out B.are to hand out C.are handing out D.is to hand out

Answer 1

D
be to do sth表示将要做某事，be doing表示正在做。而原句意思应该是即将颁奖给学生。例句：I don't know what is to be done next. 不知下一步该怎么做。
用is，这是属于主谓一致原则中“就近一致”原则，适用于"or, either... or, neither...nor, not only... but also"等句型，也就是说谓语要和后面的主语保持一致。
下面是几个例句：
You or Tom is going on business.
Neither you nor I am wrong.
Not only the students but also the teacher wishes for a holiday
希望能有所帮助:)