then

I wish I had known then what I know now.

我真希望那时我就知道现在所知道的一切。

It was then that I realised she’d tricked me.

直到那时我才知道她骗了我。

He started his career in St Petersburg – or Leningrad as it then was.

他在圣彼得堡——当时叫列宁格勒——开始他的事业。

They met in 1942 and from then on (= starting at that time ) they were firm friends.

他们1942年认识，从那时起就一直是好朋友。

Silently she closed the door. Just then she heard a noise.

她默不作声地关上了门。 就在那时，她听到有声响。

I was paid £1,000, which was a lot of money back then (= a long time ago when things were different ) in the 1950s.

他们给了我1,000英镑，在20世纪50年代那可是一大笔钱。