lie behind
US /laɪ bɪˈhaɪnd/
UK /laɪ bɪˈhaɪnd/

1.
隱藏在背後, 是...的原因
to be the real reason or explanation for something
:
•
The true motives lie behind his sudden resignation.
他突然辭職的真正動機隱藏在背後。
•
What lies behind their decision to move?
他們搬家的決定背後是什麼?