Question

I waited until Tom and Jack arrived.Then _ began

为什么不选all of them
I waited until Tom and Jack arrived.Then _ began to do the experiment。
A all of them B the three of us C three of us D both of us
为什么不能选A 。all of them 与 B the three of us 有什么区别。

Answer 1

all of us，因为前面有I。

Answer 2

I waited until Tom and Jack arrived.Then (all of us) began
all of us 指的是前面句子中提到的"I, Tom ,Jack"这三个人。

Answer 3

题目不全，无法判断