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。