Question

高中英语。主谓一致！谢谢。请说明选C的理由。。。

The boy sitting by the window is the only one of the students who ___ from the countryside in our school.
A. was B. were C. is D. are

Answer 1

我们把这句话分析一下，主语是the boy ， 后面的sitting by the window 修饰boy的状态，is是谓语，the only one of the students in our school是宾语，那么“怎么样的学生之一呢？”who ___ from the countryside 做定语修饰，所以，这里的who是指one of the students ，也就是boy，单数，所以是C

Answer 2

时态应该不用解释吧？
这里主要是理解who 引导的定语从句的先行词是什么，答案是the only one，所以用is,后面的 of the students 只是一个修饰，
但是，如果去掉only ,变成the one of the students 的话，这时就得用are ，因为先行词变成了the students

Answer 3

当关系代词在从句中作主语时，从句的谓语要根据先行词来确定，该句中先行词为the only one,单数，且主句时态为一般现在时

Answer 4

因为这个定语从句作的是the only one的定语，所以选c