感官動詞 see, watch, observe, notice, look at, hear, listen to, smell, taste, feel + do　 表示動作的完整性，真實性；+doing 表示動作的連續性，進行性
　　I saw him work in the garden yesterday.
　　昨天我看見他在花園里干活了。(強調"我看見了"這個事實)
　　I saw him working in the garden yesterday.（強調"我見他正干活"這個動作）
　　昨天我見他正在花園里干活。
　　典型例題
　　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。因題意為，他們看著她長大，因此強調的是成長的過程，而非正在長的動作，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. 本題強調其動作，正在河邊玩，應此用see sb. doing sth句型。