65. knock at the door / knock into the wall / knock out sb / knock sth off / knock sth over 敲门/撞墙/打晕某人/把……打掉/ 把……撞倒 eg. Who has knocked the vase off the shelf? / 谁把花瓶从架子上弄掉的? 66. let out the secret / keep sth a secret ...