Question

It was not until 1920 ( ) American women had the chance to vote in national elections.

为什么用that不能用when

Answer 1

强调句式It is not until sometime that...
对American women didn't have the chance to vote in national elections until 1920.进行强调，要把not until放在一起。这种强调句有一个固定的结构：It is...that，它不是时间状语从句。
如果去掉not until，变成It was 1920...的时候就要用when（It was 1920 when American women had the chance to vote in national elections.），这个时候就是时间状语从句了

Answer 2

这是强调句型！本题当中强调的是时间，不强调人，所以用that。

Answer 3

这里是强调句型，It is/was +被强调部分+that/who+从句。当被强调部分是人的话，其后的从句可以从who或者that引导，而如果是物，就只能用that引导。翻译时被强调部分就译成了“是”，“正是”，“就是”。此句的翻译时：直到20世纪初，美国妇女才取得了投票权。PS：要这么看也不比中国强多少哈~~~