1.filter的基本意思是“过滤”“滤清”,用于液体或光线等。引申可指消息“走漏”。
2.filter可用作及物动词也可用作不及物动词。用作及物动词时,接名词或代词作宾语,可用于被动结构。
3.filter接into,表示“渗入”; 接out表示“滤出”“泄露出去”; 接through,可表示“滤过”“透过”。

filter from (v.+prep.)
从…过滤出来 pass through a filter
▲filter sth from sth
◇ 用于be ～ed结构
The solid particles were filtered from the solution.固体微粒是从溶液中过滤出来的。

filter in (v.+adv.)
透过,滤过 pass or flow slowly
▲filter sth ⇔ in
Sounds of cheering filtered in through the closed window.欢呼声透过关闭的窗户传了进来。

filter into (v.+prep.)
渗透,滤过 pass or flow slowly
▲filter into sth
Water filters into the well.水渗透入井里。
Light filtered into the room.光线透进了房间。
The enemy agents managed to filter into the embattled country.敌人间谍设法钻进那个严阵以待的国家。
Foreign influence began to filter into the country.外国势力开始渗透进这个国家。

filter out (v.+adv.)
1.滤除,过滤 remove sth from a liquid
▲filter sth ⇔ out
This metal net filters out the dirt.这个金属网滤掉污物。
You have to filter out the dirt before using the water.在使用这种水之前,必须先过滤,以除去污物。
◇ 用于be ～ed结构
The solids were filtered out and only the liquid passed into the container.固体物质被过滤出来,只有液体流进容器。
2.泄漏(消息等) become known(news, etc.)
▲filter out
The news of his appointment filtered out before it was officially advertised.他被任命的消息在还没正式公布前就被透漏出去。

filter through1 (v.+adv.)
走漏 become known gradually
▲filter through
The news slowly filtered through to everyone in the office.这消息慢慢走漏出去,结果办公室的人全知道了。

filter through2 (v.+prep.)
透过,滤过 pass through gradually
▲filter through sth
A liquid filters through a strainer, into the receptacle beneath.液体经过过滤器流入下面的容器。
Water filters through the sandy soil and into the well.水透过沙土,渗透到井里。
The sunlight filtered through the curtains.阳光透过窗帘映了进来。
The sunlight filtered through the thick leaves.阳光透过茂密的树叶照射下来。
▲filter sth through sth
You filter the coffee through this special paper and it takes out the bitterness.如果你用这种特制的纸过滤咖啡,就没有苦味了。
◇ 用于be ～ed结构
The water was filtered through charcoal.这水用木炭过滤过的。

用作不及物动词
▲S+～(+A)
She went on separating, boiling, evaporating, filtering and mixing.她不断地进行分离、熬煮、蒸发、滤清、调制。
用作及物动词
▲S+～+n./pron.
Charcoal is used to filter water.木炭是用来过滤水的。
The sunglasses is used to filter the light.太阳镜用于滤光。
◇ 用于be ～ed结构
Water and soil would have to be filtered many times to remove any radioactive matter.水和土壤须经过多次过滤以消除放射性物质。

［同义词］ n. strainer
［词源］＜中古拉丁语fitrum(毛毡)

The lake water passes through a filter before it is piped to our homes.湖水过滤后用管道输送到各家各户。
They purified water by a filter.他们用过滤器净化水。