Question

这个是什么从句？

Tom was the only one of the studetnts who was late this morning

Answer 1

这个复合句中含有定语从句，即先行词student后面的who was late this morning.是定语从句。

Answer 2

您好，这个是定语从句。您可以看一下译文：汤姆是最后一个到教室的。

Answer 3

Tom was the only one of the studetnts who was late this morning.
who引导定语从句，先行词是the only one
汤姆是今天早上唯一迟到的学生。
区别：Tom was one of the studetnts who were late this morning.
定语从句先行词是the students, 所以，应用were

汤姆是今天早上迟到的学生之一。

追问

但是，前面the only one of the 复数名词，后面应该使用动词单数

追答

one前面有the，先行词就是one；one前面没有the，先行词就是of后的名词。
认真看一下区别。

Answer 4

您好，您的这个句子有点问题，因为 the only one（唯一的一个）不能和 one of the students（多个学生中的一个）共同使用，所以句子可以是：

1）Tom was the only one who was late this morning.
who 引导定语从句修饰 one（作名词）

2）Tom was the only student who was late this morning.
who 引导定语从句修饰 student

3）Tom was one of the students who was late this morning.
who 引导定语从句修饰 one

Answer 5

这是定语从句，主句是who前面的部分，从句是who以后的，who做关系代词，意思是：这个男孩是今天早晨唯一一个迟到的学生。