from的用法是：two miles from shore，away from danger，far from home，to take two from four。
from [强frɔm; 弱frəm]
prep.
距,离,在不近的地方；与…失去联系(常与away连用)：
two miles from shore
离海岸两海里
away from danger
远离危险
far from home
远离家乡
离开(整体),脱离统一体(或联盟)：
to take two from four
四减二
She was absent from factory for three weeks.
她三周没有去工厂上班了.
失去…的可能性(或用处)；去除,免掉,阻止：
to be kept from going
不让走
摆脱…的占有(或控制)：
released from jail
释放出狱
protection from sun
防晒
从,自,由；从…开始：
to go from London to Paris
从伦敦到巴黎
to leave from the station
从车站离开
from start to finish
自始至终
从…起：
from noon to midnight
从中午到半夜
He has been a sick man from youth.
他从年轻时就一直是个病夫.
出于；出自(何处)；由…而来,从…来,由…出来,由…产生：
Flour is made from wheat.
面粉是由小麦制成的.
to take a comb from the pocket
从口袋掏出一把梳子
根据,依据；把(某人或某物)作为制造者、发送者、发言者、教师等：
From the evidence,he must be guilty.
根据此证据,他肯定有罪.
a letter from Mary
玛丽的来信
facts learned from reading
从阅读中获得的事实
[表示过去、一段时期、距离、动作等的起点；表示思想、行动等的根源、来源或起源]
[表示距离、缺席、排除、分离、排斥、防止、解救、脱离、离开等]
[表示差异、区别、比较等]识别,区别开来：
to know right from wrong
分清是非
to tell one from another
把东西区别开来
(表示理由、原因、动机等)因,因为,由于,出于,由…引起：
to tremble from fear
怕得发抖
to suffer from a cold
患感冒
to do something from motives of jealousy
出于妒忌干某事