[T, I] to examine sth very carefully in order to decide what is important or useful or to find sth important 细查；详审
~ sth
We will sift every scrap of evidence.
我们将细查每一点证据。
~ through sth
Crash investigators have been sifting through the wreckage of the aircraft.
调查坠机事件的专家一直在仔细检查飞机残骸。