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。
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。
adv. thence、 thenceforth