1. At that time, America and Britain were at war.

at that time 在那时；当时
例句：At that time, his view was extremely controversial.
当时，他的观点极具争议。

2. It is also known as "My Country 'Tis of Thee."

known as 被认为是,被称为
例句：That's known as a perturbative approach.
这就是所谓的摄动法。

3. The music is the same as the British national song, "God Save the Queen."

the same as 与…同样的
例句：Just do the same as me.
跟着我做就行了。