主句过去完成时,从句过去将来时

sentence:
  U are going to far..
  Don't bury your head in the sand..
  What happened to your momery?
  I have no other choice..
  I am afraid all my efforts were in vain.. 
 
key words and expressions:
  vain          徒然的,无益的              bury               埋葬,掩埋
  steal         偷,偷窃                          guard              守卫,保卫
  sand          沙子                              grain              谷物,颗粒
  pile          堆,堆起                            The Customs House  海关
  Africa        非洲                               parcel             小包,包裹
  valuable      贵重的,有价值的        expect             期待,预期           
  detective     侦探                             airfield           飞机场
  precious      珍贵的,宝贵的             while              与此同时,但是
  whereas       然而,反之,但是            to one's surprise  令某人意外的
  kick          踢                         to one's disappointment        使某人失望的

pattern drill: 
  My mother is watering the garden while my farther is reading newspaper..
  He is hard working while(whereas) his brother is lazy..
  They were expecting a valuable parcel of diamonds from South Africa.
  He kicked the snow off his shoes before getting in..

syntax: 
  介词==> at/from/inside/on/off/into/at
  waiting at the airport
  a diamonds from Nigeria
  waiting inside the main building
  waiting on the airfield
  take the painting off the wall
  carry it into the Customs House
  keeping guard at the door
  主句过去完成时,从句过去将来时..
  A few hours earlier some one had told the police that thieves would try to steal the diamonds.
  过去进行时..
  Some of the detectives were waiting inside the main building while others were waiting on the airfield..