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，+doing 表示动作的进行性。例如：
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。
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。