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。