8.12 感官动词 + doing/to do
 
  感官动词 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do  表示动作的完整性,真实性;+doing 表示动作的连续性,进行性
 
 I saw him work in the garden yesterday.
 昨天我看见他在花园里干活了。(强调"我看见了"这个事实)
 I saw him working in the garden yesterday.(强调"我见他正干活"这个动作)
 昨天我见他正在花园里干活。

典型例题
1)They knew her very well. They had seen her ___ up from childhood. 
  A. grow  B. grew  C. was growing  D. to grow
  答案:A。因题意为,他们看着她长大,因此强调的是成长的过程,而非正在长的动作,因此用see sb do sth 的句型。

2)The missing boy was last seen ___ near the river. 
 A. playing  B. to be playing  C. play  D. to play
 答案A. 本题强调其动作,正在河边玩,应此用see sb. doing sth句型。