whether是名词性从句中的什么词

名词性从句包括主语从句，宾语从句，表语从句和同位语从句.

whether用于主语从句：

Whether I knew John doesn't matter.

whether用于宾语从句：

It all depends on whether we can get their cooperation.（注意：本句it是代词）

whether用于表语从句：

The question is whether we can finish our work by tomorrow evening.

whether用于同位语从句：

The question，whether we need it，has not yet been considered

whether是名词性从句中的连接词，具体内容如下。

从结构上说，英语连接词分两大类：并列连词（coordinating conjunctions）和从属连词（subordinating conjunctions）。

并列连词连接两个或两个以上地位平等的字、词组或分句。例如：(1) Air and water are indispensable to me.

(2) She likes going out with friends or playing outdoor games.