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。