落后 → ☊ 
to fall behind; to lag (in technology etc); backward; to retrogress ☊ 
sau đằng sau sau khi 
after like: Đằng sau → →
hinten ☊ 
Đẳng sau ☊ 
后面 ☊ hòu miàn der Hintergrund ☊ Đằng sau ☊ ☊ hinten ☊ Đẳng sau ☊ ☊ Im Hintergrund ist Natur zu sehen: eine umzäunte Wiese und ein Wald. ☊ Đằng sau có thể thấy thiên nhiên: Một bãi cỏ được rào quanh và một cánh rừng. ☊ (Lektion 57, Nr. 809) I had fallen so far behind that it seemed pointless trying to catch up. ☊ behind ☊
behind (in sth): He was terribly behind in his work. ☊ behind ☊
behind enemy lines (= the area controlled by the enemy) ☊ enemy ☊
Do you think it's funny to make faces behind my back? ☊ pull/make faces/a face (at sb) ☊
Ron is the driving force (= the person who has the most influence) behind the project. ☊ force ☊
Behind him, a horn blared. ☊ horn ☊
imagine (that)...: He's always imagining (that) we're talking about him behind his back. ☊ imagine ☊
An impatient driver behind me sounded his horn. ☊ impatient ☊
She knifed him in the back. ☊ knife ☊
leave sth/sb behind: Don't leave any of your belongings behind. ☊ leave ☊
Your feet must be behind the line when you serve (= in tennis ). ☊ line ☊
I fail to see the logic behind his argument. ☊ logic ☊
He walked out leaving a pile of debts behind him. ☊ pile ☊
The principle behind it is very simple. ☊ principle ☊
She explained the thinking behind the campaign. ☊ thinking ☊
unite (behind/against sb/sth): Will they unite behind the new leader? ☊ unite ☊