on + doing..

sentence:
  I am working on it./U bet!/No wonder./U cannot please everyone.
  He owes my uncle $100./How r things going?/I know all about it.
  Did u miss the bus?/Donot lose yourhead./He cannot take a joke.

key words and expressions:
  intransitive    不及物的                   transitive     及物的
  shore           海岸,支撑                   coast          海岸,滑坡
  boast           自夸,以有..自豪         cliff          绝壁,悬崖
  set out         出发,动身                    struggle       奋斗,努力,竞争,挣扎
  towards evening 天快黑的时候      on the whole   大体上,基本上
  ahead           朝,在..前面                 Platonic       柏拉图哲学的,理想的
  Plato           柏拉图                         trembling      发抖,战粟

Pattern:
  He found himself unable to say anything on an occasion like this.
  I found myself in a strange place.
  She found herself trembling.
  All [that] u can do is to wait.      that引导的定语从句,做宾语时可省略  
  The light was high up on the clifts.                                         up做方位词
  The girl struggled up the cliff towards the light she had seen. 同上

Syntax:
  on + 动名词... === as soon as.... 一...就...
  On entering the gate,he was stopped by the guard.
  On seeing the man,she waved and called out to him.
  before 做时间状语时,可理解为 过了多久....才...[连词]
  It was three days before he came back.
  The phone had rung for one minute before someone answered it.
  Nearly a week passed before the girl was able to explian what had happened to her.
  v.i. 不及物动词,后面如果要加名词必须先加介词
  v.t. 及物动词,可以直接加名词